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Excelsior Scientific.book - Spectra

1. Notes 4 Notes Notes 5 Excelsior Diode Pumped CW Lasers Notes 6 Report Form for Problems and Solutions We have provided this form to encourage you to tell us about any difficulties you have experienced in either using your Spectra Physics instrument or its manual problems that did not require a formal call or letter to our service or marketing departments but that you feel should be remedied We are always interested in improving our products and manuals and we appreciate all suggestions Send all instrument related questions to Send all manual related questions to Spectra Physics Spectra Physics A Newport Corporation Brand A Newport Corporation Brand Service Manager Senior Director Product Marketing 3635 Peterson Way 3635 Peterson Way Santa Clara CA 95054 Santa Clara CA 95054 FAX 408 980 3584 FAX 408 980 7101 Thank you From Name Company or Institution Department Address Instrument Model Number Serial Number P
2. Figure 3 7 Outline Drawing of the Excelsior DPSS CDRH Laser Head 3 12 0 83 Dimensions given in inches mm 21 4 53 E 115 if NN E 1 97 AE AAA AA Oa A 50 Ni E 0 28 3 98 70 101 3 0 75 19 014 _ 4 25 0 18 3 5 108 a Y ID A 0 01 goo E c DM A OF 17 43 5 4 03 5 b System Description 03 p Wx4L Figure 3 8 Outline Drawing of the Excelsior DPSS XC CDRH Laser Head 3 13 Excelsior Diode Pumped CW Lasers is 5 5 140 EMISSION S O POWER ENABLE STABLE SERVICE EMISSION e 3 O O O O O 2 75 70 d Y A 0 25 Dimensions given in inches 6 6 5 7 1 465 PS CDRH or gg PS XC CDRH 7 Figure 3 9 Outline Drawing of Excelsior Power Supply Controller 3 14 Chapter 4 Controls Indicators and Connections This section defines the user controls indicators and connections of the Excelsior laser head and power supply Chapter 6 describes how to use these features to operate the laser The Excelsior Laser Head Shutter O Ao Laser Beam a 5 LATA Figure 4 1 The Standard Excelsior Laser Head
3. Controls Shutter is opened and closed by means of the lever on the top of the laser head near the output end The shutter is open when it is pushed to the left when looking in the direction of the laser beam to the OPEN position Shutter Shutter U UI c O O Y i 4T a 1 of O Standard Laser Head XC Laser Head Figure 4 2 Shutter Open Close Designations 4 1 Excelsior Diode Pumped CW Lasers Connections LASER cable connector rear panel not shown provides connection for a control cable supplied that provides control signals and power to the laser head from the power supply controller One of two types of connec tors is present e the Excelsior CDRH laser head has a 26 pin SDR connector e the Excelsior XC CDRH laser head has an HD 15 pin D sub connector Excelsior Power Supply Controller Front Panel EMISSION POWER ENABLE STABLE SERVICE EMISSION O O O O O E Figure 4 3 The Power Supply Controller Front Panel Two power supplies are available for the Excelsior series lasers one for the standard laser head and one for the extended laser head They appear to be the same but some functions differ slightly These differences are noted below under standard and extended Controls EMISSION keyswitch provides interlock safety to prevent unauthorized personnel from using the laser when the key is turned to the STBY position an
4. VISIBLE AND OR INVISIBLE VISIBLE AND OR INVISIBLE LASER RADIATION LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION DIRECT OR SCATTERED RADIATION LASS 3B LASER PRODUCT CLASS 4 LASER PRODUCT 473 505 515 532 542 561 594 NM WAVELENGTH 1064 NM WAVELENGTH MAXIMUM OUTPUT POWER 500 mW MAXIMUM OUTPUT POWER 1 5 W Figure 2 1 These standard safety warning labels are appropriate for use as entry warning signs EN 60825 1 2007 ANSI Z136 1 Section 4 7 Figure 2 2 Folded Metal Beam Target 2 2 Laser Safety Danger Use of controls or adjustments or performing the procedures described AE in this manual in a manner other than specified may result in hazardous radiation exposure Danger Operating this laser without due regard for these precautions or in a W manner that does not comply with recommended procedures may be dangerous At all times during installation maintenance or service of your laser avoid unnecessary exposure to laser or collateral radiation that exceeds the accessible emission limits listed in Performance Stan dards for Laser Products United States Code of Federal Regulations 21CFR1040 10 d Any electronic product radiation except laser radiation emitted by a laser product as a result of or necessary for the operation of a laser incorporated into that product Follow the instructions contained in this manual to
5. The Excelsior laser head requires no routine maintenance There is no rea son to remove the outer cover because there are no user serviceable parts inside the laser head This cover should only be removed by an authorized service engineer To retain a clean intracavity environment all components are cleaned to stringent standards prior to assembly and alignment at the factory The cover of the laser module inside the laser head is secured and sealed and should never be opened Removing the module cover will compromise the cleanliness of the intracavity space degrade laser performance and void the warranty Replacing the diode pump laser can only be performed at a Spectra Physics facility by someone trained and authorized by Spectra Physics Call your Spectra Physics service representative when you suspect that the diode pump laser is at its end of life e g the Service indicator has turned on All parts that normally come in contact with laboratory or industrial envi ronments retain surface contamination that can be transferred to optical components during handling Indeed skin oils can be very damaging to optical surfaces and coatings and can lead to serious degradation problems under intense laser illumination It is therefore essential that only clean items come into contact with optical components and to the mechanical parts immediately surrounding them Excelsior Diode Pumped CW Lasers Service Training Programs Excels
6. This user information is in compliance with section 1040 10 of the CDRH Laser Products Performance Standards from the Health and Safety Act of 1968 Hazards associated with the use of diode pumped lasers generally fall into the categories listed below At all times while working with these lasers please be aware of these potential hazards and act accordingly You are responsible for your health and the health of those working around you e Exposure to laser radiation can result in damage to the eyes or skin e Exposure to chemical hazards such as particulate matter or gaseous substances can be health hazards when they are released as a result of laser material processing or as by products of the lasing process itself When these lasers are used to pump dye laser systems be aware that the dyes used can be extremely hazardous to your health if inhaled or in some cases even touched Exposure to high voltage electrical circuits present in the laser power supply and associated circuits can result in shock or even death e Possible health risks are present if pressurized hoses cylinders liquids and gasses used in laser systems are damaged or misused 2 1 Excelsior Diode Pumped CW Lasers Precautions for the Safe Operation of Class Illb High Power Lasers e Wear protective eyewear at all times selection depends on the wave length and intensity of the radiation the conditions of use and the visual function required Protect
7. where h is Planck s constant and vis the frequency of the photon Likewise when an atom excited to E decays to E it loses energy equal to E E The atom may decay spontaneously emitting a photon with energy hv and frequency Ej E 2 Light will be used to describe the portion of the electromagnetic spectrum from the infrared to the ultraviolet Excelsior Diode Pumped CW Lasers Population Inversion 3 2 Spontaneous decay can also occur without emission of a photon An atom excited to E can also be stimulated to decay to E by absorbing a photon of frequency v then emitting a pair of photons that are identical to the inci dent one in phase frequency and direction This is known as stimulated emission By contrast spontaneous emission produces photons that have no directional or phase relationship with one another A laser is designed to take advantage of both stimulated and spontaneous emission and absorption as well using them to create conditions favorable for light amplification The following paragraphs describe these condi tions A material in thermal equilibrium has most of its atoms or molecules in their ground state As a result the rate of absorption of incident light at all frequencies exceeds that of emission If enough light at the correct frequency v is supplied electrons in a lower energy level will absorb light energy and shift to an upper level until the populations of two levels are equ
8. Diode Laser Mode Volume TEMoo Mode Volume _ Gain Region NG Lasing Medium Figure 3 5 Mode Matching Frequency Doubling System Description In the Excelsior the infrared output from a neodymium based laser crystal is converted to visible light through frequency doubling also called sec ond harmonic generation in a nonlinear crystal Frequency doubling occurs when an intense laser beam enters a nonlinear crystal and generates a second beam at half the incident wavelength The blue Excelsior lasers use a lithium triborate LBO crystal as the doubling medium the green lasers use a potassium titanyl phosphate KTP crystal Phase matching is a requirement of nonlinear optics to achieve an efficient conversion of the fundamental incident light to a new wavelength To pro duce any significant output at the new wavelength the fundamental light wave and the converted light wave must stay in phase over a sufficient length in the nonlinear material to allow the conversion to take place In most nonlinear materials however the indices of refraction at the two wavelengths will be significantly different causing the two waves to become rapidly out of phase unless special techniques are employed One such technique takes advantage of the birefringence of nonlinear crystals The indexes of refraction of the two light waves can be made to match exactly if the direction of propagation and the polarization orien
9. 561 594 nm 542 561 594 nm 561 594 nm CE Rayonnement laser Laserstrahlung Radiaci n l ser Laser straling Danger Exposition Dan Bestrahlung ver Evite la exposici n Vermijd blootstelling Label gereuse Appareil a meiden Producto l ser Clase Klasse 4 laser 4 laser de Classe 4 Laser Klasse 4 4 produkt Puissance maxi Maximale Aus Potencia m xima Max output ver mum 1 5 W gangsleistung 1 5 W 1 5W mogen 1 5 W Longueur d onde Wellenl nge 473 Longitud de onda Golflengtebereik 1064 nm 1064 nm 1064 nm 1064 nm Patent Ce produit est fab Dieses Produkt Este producto esta Dit product is gefabri Label riqu sous l un ou wurde unter Verwen fabricado con una o ceerd met een of 8 plusieurs des bre vets suivants des Etats Unis dung einer oder mehrerer der fol genden US Patente hergestellt m s de las siguientes patentes de los Esta dos Unidos meer van de vol gende USA patenten Excelsior Diode Pumped CW Lasers Waste Electrical and Electronic Equipment Recycling Label 2 12 To Our Customers in the European Union As the volume of electronics goods placed into commerce continues to grow the European Union is taking measures to regulate the disposal of waste from electrical and electronic equipment Toward that end the Euro pean Parliament has issued a directive instructing European Union member states to adopt legislation concerning the reduction recovery re use and recycling of waste electrica
10. 742 2020 Internet http www acgih org home htm Laser Institute of America 13501 Ingenuity Drive Suite 128 Orlando FL 32826 Tel 800 345 2737 Internet http www laserinstitute org International Electrotechnical Commission Journal of the European Communities IEC 60825 1 Safety of Laser Products Part 1 Equipment classification requirements and user s guide Tel 41 22 919 0211 Fax 41 22 919 0300 Internet http www iec ch Cenelec 35 Rue de Stassartstraat B 1050 Brussels Belgium Tel 32 2 519 68 71 Internet http www cenelec eu Document Center Inc 111 Industrial Road Suite 9 Belmont CA 94002 Tel 650 591 7600 Internet http www document center com 2 13 Excelsior Diode Pumped CW Lasers Equipment and Training 2 14 Laser Safety Guide Laser Institute of America 13501 Ingenuity Drive Suite 128 Orlando FL 32826 Tel 800 34LASER Internet http www laserinstitute org Laser Focus World Buyer s Guide Laser Focus World Pennwell Publishing 98 Spit Rock Road Nashua NH 03062 Tel 603 891 0123 Internet http pennwell 365media com laser focus world search html Photonics Spectra Buyer s Guide Photonics Spectra Laurin Publications Berkshire Common PO Box 4949 Pittsfield MA 01202 4949 Tel 413 499 0514 Internet http www photonics com Chapter 3 System Description A Brief Review of Laser Theory Emission and Absorption of Light
11. Excelsior 542 50 Excelsior 561 25 Excelsior 561 50 Excelsior 561 100 Excelsior 561 150 Excelsior 594 50 Excelsior 1064 500 Excelsior 1064 800 These lasers will only operate at constant full power when the PWR CONTROL switch is set to INT These lasers meet specified parameters only at 10096 laser output power External Control Connector The following directions are provided if you intend to operate the laser remotely using the CONTrol interface connector l Set the EMISSION CONT and or the PWR CONT switches to EXT as appropriate The PWR CONT switch should be set to EXT for remote control only for the lasers listed in Table 5 2 Otherwise this switch should be set to INT for all lasers for continuous maximum output power Connect a cable with a 15 pin D sub connector to the CONTrol con nector The pin numbering sequence is shown in Figure 5 4 as you look at the power supply connector Numbers proceed from right to left Pin 2 provides on off control Pin 8 provides power output con trol Use one of the ground pins Pins 6 7 11 or 12 for reference Ground Pin descriptions are given in Table 5 3 Directions for oper ating the laser remotely are provided in Chapter 6 Figure 5 4 External CONTrol Interface Connector Pin Numbering Installation Table 5 3 External Control CONT Connector Pin Functions Pin Type Description Function 1 Output Laser STABLE This pin becomes internally shorted to grou
12. Excelsior Diode Pumped CW Lasers Customer Service Warranty At Spectra Physics we take great pride in the reliability of our products Considerable emphasis has been placed on controlled manufacturing meth ods and quality control throughout the manufacturing process Neverthe less even the finest precision instruments will need occasional service Our instruments have excellent service records compared to competitive prod ucts and we strive to provide excellent service to our customers in two ways by providing the best equipment for the price and by servicing your instruments as quickly as possible When calling for service inside the United States dial our toll free number 1 800 456 2552 To phone for service in other countries refer to Service Centers on page 7 7 Order replacement parts directly from Spectra Physics For assistance of any kind contact your sales office or service center You will need your model and serial numbers available when you call To order optional items or other system components or for general sales assistance dial 1 800 SPL LASER in the United States or 1 408 980 4300 from anywhere else All parts and assemblies manufactured by Spectra Physics are uncondi tionally warranted to be free of defects in workmanship and materials for the period of time listed in the sales contract following delivery of the equipment to the F O B point Liability under this warranty is limited to repairing
13. ing etc insist that a representative of the carrier be present when you unpack the contents Carefully inspect your laser system as you unpack it If any damage is evi dent such as dents or scratches on the covers etc immediately notify the carrier and your Spectra Physics sales representative Keep the shipping container If you file a damage claim you may need it to demonstrate that the damage occurred as a result of shipping If you need to return the system for service at a later date the specially designed con tainer assures adequate protection System Components Accessories Two components comprise an Excelsior laser system e Excelsior laser head e Excelsior power supply The power supply and laser head are fairly light and can be handled easily by one person Verify both components are present The laser head and power supply are shipped in one container Included with the laser is this manual a packing slip listing all the parts shipped and an accessory kit The following accessories are shipped stan dard with the system e LASER HEAD cable 1 8 m 6 ft e REMOTE interlock jumper plug e power cord Japan 2 m PSE compliant All others 2 m UL CSA compliant and 2 5 m SEMKO NEMKO FIMKO DEMKO KEMA VDE SEV and VE compliant e 2 sets of keys XV Chapter 1 Introduction General Information Figure 1 1 The Standard DPSS Excelsior Laser Head Spectra Physics Excelsior lasers prod
14. 4 for instructions 9 Output 12 Vdc This pin provides 12 Vdc 20 mA max This output can be used for external power control or for driving an external LED for indicating status 10 Output SERVICE Alarm Indicates the diode pump laser in the laser head is nearing its end of life To employ this open collector alarm refer to Using the Service Alarm Signal Pin 10 on page 6 4 11 Ground 12 Ground 13 N A or Reserved or Must be open on an Excelsior PS CDRH or it provides a Output Thermistor Alarm thermistor alarm on a Excelsior PS XC CDRH For the lat ter it indicates that the thermistor circuit inside the laser head has opened To employ this open collector alarm refer to Using the Thermistor Alarm Pin 13 on page 6 6 14 N A Reserved Must be open 15 N A Reserved Must be open LASER connector provides power control and monitoring to and from the laser head This connector mates to the 1 8 m 6 ft control cable which restricts the laser head to the CDRH maximum distance from the EMISSION indicator on the power supply Two types of connectors are used e a26 pin 3M SDR connector is used on the Excelsior PS CDRH power supply e a standard 15 pin D sub connector is used on the Excelsior PS XC CDRH power supply Controls on the Power Supply Side Panel 4 6 Te ae n E UJ Fi
15. Alarm I Indicator I I Pin 13 45V i Thermistor Alarm Signal active low Gnd O0 Gnd Power Supply l External Circuit Figure 6 7 Thermistor Alarm Example Circuit Interlock Jumper Plug An interlock jumper plug Figure 6 8 is provided with the system to allow operation without an optional external safety interlock circuit wired to the REMOTE connector Make sure that either a normally closed NC switch or shorting device is wired to this connector or if none is to be used that the jumper plug is installed Figure 6 8 REMOTE Interlock Jumper Plug 6 7 Excelsior Diode Pumped CW Lasers 6 8 Chapter 7 Danger Laser Radiation Eyewear D Required Maintenance Troubleshooting and Service The Spectra Physics Excelsior lasers are Class IIIb and Class 4 High Power Lasers whose beams are by definition safety hazards Take pre cautions to prevent accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye damage Because the infrared IR beam of the 1064 nm lasers is invisible it is especially dangerous Infrared radiation passes easily through the cor nea of the eye which when focussed on the retina can cause instanta neous and permanent damage Always wear proper eye protection when working on the laser and fol low the safety precautions in Chapter 2 Laser Safety Refer to the product model number label for wavelength nm
16. connec tion to the CONTrol interface connector on the back of the power supply The power supply provides low noise regulated high current to the laser head to drive the diode laser The power supply is auto ranging and requires a single phase ac electrical source of 90 264 Vac at 47 to 63 Hz The Excelsior PS CDRH requires a maximum of 40 W of ac power and is capable of providing 13 W of dc power to a standard laser head The Excel sior PS XC CDRH requires a maximum of 70 W of ac power and is capa ble of providing 28 W of dc power to an XC laser head Thermal Management Management of the heat load produced by the laser is critical to maintain ing its specified output The laser head must be mounted on a heatsink capable of maintaining its baseplate temperature below 50 C but greater than 10 C The diode pump laser in the laser head will produce several watts of waste heat that must be removed through the baseplate by the heat sink see Figure 5 1 Cooler ambient temperatures for the environment of the laser will make the job of dissipating waste heat through the baseplate easier see Figure 5 2 The Excelsior power supply produces a significant current load to power the thermo electric cooler TEC inside the laser head Consequently a reliable means to remove waste heat from the power supply must be pro vided as well The relatively large heatsink on the side of the power supply is sufficient to remove heat from the inside of t
17. is still in the ON position the keyswitch must first be turned off then back on again in order to resume operation After it is turned back on the EMISSION indicator turns on again and the laser will turn on again after a safety delay of 3 to 5 seconds Pin 1 of the CONTrol connector can be used to control an external emission indicator See Chapter 6 for an example of a circuit used for this purpose Excelsior Diode Pumped CW Lasers Back Panel FUSE REMOTE CONT 100 240V 50 60Hz es Figure 4 4 The Power Supply Controller Back Panel Connections AC POWER connector provides attachment for an IEC power cable The cable provides ac power to the system and accepts service from 47 to 63 Hz at 90 to 264 Vac FUSE holder holds a 5 2 mm x 20 mm fast acting cartridge fuse The required fuse is e Excelsior PS CDRH 250 V 1A Excelsior PS XC CDRH 250 V 2 A REMOTE interlock connector 2 pin provides attachment for a user supplied safety switch These contacts must be shorted together before the laser will operate A defeating interlock jumper plug Figure 4 5 is installed at the factory to permit operation without a safety switch Figure 4 5 REMOTE Interlock Jumper Plug To turn on the laser again following an interlock fault when the two con tacts were opened close the contacts again resolve the fault issue and do one of the following On a
18. neodymium ions are very efficient at absorbing the diode laser light which excites them to the pump bands shown in the fig ure The excited electrons quickly drop to the F3 level the upper level of the lasing transition where they remain for a relatively long time The most probable laser transition is to the 1 State which emits photons at 1064 nm Because electrons in that state quickly relax to the ground state the population of this state remains low Hence it is easy to build a population inversion where the number of electrons in the higher energy level exceeds the number in the lower level There are several different laser transitions in neodymium that start from the same upper state These transitions compete for the same population of electrons and if left to themselves the 1064 nm transition will dominate The blue Excelsior lasers employ vanadate Nd Y VO crystals to produce the 1064 nm wavelength for doubling to 532 nm Vanadate is a popular solid state laser material for small to medium power solid state lasers due to its low threshold for lasing along with its large cross section for stimu lated emission Neodymium can be made to lase at other wavelengths at 946 nm in partic ular This 946 nm transition has a lower gain and a higher threshold than the 1064 nm transition When lasing at this wavelength is desired it can be achieved by choosing the proper wavelength selective coatings for the res on
19. power level Figure 6 5 shows two simple external circuits for making these adjust ments Table 6 2 lists the recommended parameters for R and VR Note that although the input at Pin 8 is shown as 0 to 5 V this corresponds to 0 to 100 of output power whereas actual adjustment should only go from 50 to 100 output power INT Pin 9 1 Pin 8 R I Input Impedance I VR Zu I I Gnd I Power Supply I External Circuit I Pin 8 Ri Vde 12 V I Input Impedance I VR Zin Gnd I I Power Supply 1 External Circuit Figure 6 5 Example Circuits for Varying Laser Output Power Table 6 2 Recommended Parameters for R and VR in Figure 6 5 Input Voltage to Pin 8 Controller Impedance Value for VR Value for R Corresponding to Zin 0 100 output power 1k0 1 2 kO 2k0 2 2 kO Excelsior PS CDRH 18 kO 5 KO 51 KO 0V 5V 10 KQ 8 2 kO 1 kO 1 2 kO 2k0 24 kO Excelsior PS XC CDRH V 5V xcelsior PS XC C 26 kO 5 KO 56 kQ 0 5 10 KQ 9 1 kO f Vdc in the bottom figure is not 12 V the resistance of VR and R should be modified accordingly Excelsior Diode Pumped CW Lasers Monitoring Laser Output Power Pin 5 Laser output power can be monitored remotely at Pin 5 which provides an output signal that is approximately proportional to laser output power Actual output at Pin 5 depends on laser model For example Excelsior PS CDRH At full output power the signal is 95 to 100 mV Example a P
20. shows the emission spectra of a diode laser compared to a black body source The near perfect overlap of the diode laser output with the Nd absorption band ensures that the pump light is efficiently coupled into the laser medium Any pump light not coupled into the medium must ultimately be removed as heat 3 5 Excelsior Diode Pumped CW Lasers c 2 amp o o ag A O z 0 5 0 6 0 7 0 8 E 0 9 gt Wavelength um 2 __ Black Body 2 Source 3000 K b 5 o Diode Laser E Pump Wavelength E Wi 0 6 0 7 08 0 9 Wavelength um eo u Figure 3 4 Nd absorption spectra compared to emission spectra of a Black Body Source a and a Diode Laser b One of the key elements in optimizing the efficiency of a solid state laser is maximizing the overlap of the regions of the active medium excited by the pumping source and the active medium occupied by the laser mode The maximization of this overlap is often called mode matching and in most applications TEM is the laser mode that is most desired A longitudinal pumping geometry provides this sort of optimal mode match Longitudinal pumping allows the diode laser output to be focused on a vol ume in the active medium that best matches the radius of the TEM mode In general the TEM mode radius is chosen to be as small as possible to minimize the solid state laser threshold Figure 3 5 shows a schematic of a mode matching design of this type
21. standard Class 3b Laser if the keyswitch is still in the ON posi tion the laser will turn on again automatically after a safety delay of 3 to 5 seconds On a standard Class 4 laser the keyswitch must be turned off then back on again in order to resume operation following a safety delay of 3 to 5 seconds Controls Indicators and Connections On an extended cavity laser if the keyswitch is still in the ON position the laser will turn on again automatically after a safety delay of 3 to 5 seconds CONTrol connector HD 15 pin D sub female provides various optional external control functions Examples for controlling the laser using these functions are given in Chapter 6 Operation The user is to provide the control cable Each pin function is described in Table 4 1 The pin numbering sequence is shown in Figure 4 6 as you look into the panel connector Numbering proceeds from right to left Refer to Chapter 6 for circuit descriptions 5 1 AS 15 11 Figure 4 6 External Control Connector Pin Numbering Table 4 1 External Control CONT Connector Pin Functions Pin Type Description Function 4 Output Input Output Output Output Ground Ground Laser STABLE This pin becomes internally shorted to ground through a transistor when the laser reaches stable operation i e when laser output power is at the specified level and sta ble and laser head temperature is within the proper oper
22. the beam The spectral content of the light in this mode arises from the standing waves formed along the axis of the cavity with frequencies determined by the separation between the resonator mirrors The difference in frequency Af between any two of these longitudinal modes is given by We 3 where c is the speed of light n is the refractive index and is the distance between the cavity mirrors The number of such longitudinal modes in the laser output is determined by the number of such modes that fall under the bandwidth of the gain material as shown in Figure 3 2 C Longitudinal Modes Gain Envelope 6 10 GHz FWHM Point Gain Frequency v Figure 3 2 Frequency Distribution of Longitudinal Modes Excelsior Diode Pumped CW Lasers Single Longitudinal Mode Operation Some laser applications benefit from a beam with only a single longitudi nal mode From equation 3 it can be seen that reducing the separation between the resonator mirrors will increase the frequency spacing of the longitudinal modes and sometimes enable only a single mode to remain within the gain bandwidth of the laser material Often however the gain bandwidth is so large that the mirror separation would have to be impracti cally short to result in only a single mode remaining Although the Excel sior lasers are very small they still produce numerous longitudinal modes due to the broad gain bandwidth of the neodymium based crys
23. values Table 1 2 Excelsior Power Supply Controllers Power Supply Models Used With These Lasers Excelsior 473 10 50 CDRH Excelsior 532 20M CDRH Excelsior 532 50 100 150 200 CDRH Excelsior 542 50 CDRH Excelsior 561 25 50 CDRH Excelsior 1064 500 800 CDRH Excelsior 505 20 CDRH Excelsior 515 50 CDRH Excelsior 532 300 CDRH Excelsior 561 100 150 CDRH Excelsior 594 50 CDRH Excelsior PS CDRH Excelsior PS XC CDRH Introduction Patents The Excelsior lasers are manufactured under one or more of the following US patents 4 756 003 4 872 177 5 870 415 7 189 703 3 046 562 Japanese patent Excelsior Diode Pumped CW Lasers Chapter 2 Danger Laser Radiation Note a General Hazards Laser Safety The Spectra Physics Excelsior lasers are Class IIIb and Class 4 High Power Lasers whose beams are by definition safety hazards Take pre cautions to prevent accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye damage Because the infrared IR beam of the 1064 nm lasers is invisible it is especially dangerous Infrared radiation passes easily through the cor nea of the eye which when focussed on the retina can cause instanta neous and permanent damage Always wear proper eye protection when working on the laser and fol low the safety precautions given in this chapter Refer to the product model number label for wavelength nm
24. which when focussed on the retina can cause instanta neous and permanent damage Always wear proper eye protection when working on the laser and fol low the safety precautions in Chapter 2 Laser Safety Refer to the product model number label for wavelength nm Detailed descriptions of signals and connectors are given in Chapter 4 Controls Indicators and Connections Operating the Laser from the Power Supply The simplest way to operate the laser is to allow it to run at constant max imum power and to use the EMISSION keyswitch on the power supply to turn the laser on and off Turning the Laser On and Off 1 Always start the laser with the shutter closed Also be sure that the beam will be terminated by the target a power detector or other suit able beam block Turn on the POWER switch The POWER indicator will illuminate The laser head will take 2 to 5 minutes to reach operating temperature at which time the ENABLE indicator will turn on Turn on the EMISSION keyswitch The EMISSION indicator will illumi nate and after a CDRH delay of 3 to 5 seconds the Excelsior will pro duce laser radiation Note a If the EMISSION keyswitch is turned on before the ENABLE indicator turns on the laser will not start If this happens turn off the keyswitch and turn on the keyswitch Then turn on the keyswitch on again 6 1 Excelsior Diode Pumped CW Lasers 4 Wait a few seconds for laser output pow
25. 1 1 Excelsior Diode Pumped CW Lasers Excelsior laser heads are completely interchangeable with same models as are the power supplies In case the laser head or power supply needs to be exchanged the new unit is simply fastened in place and the cabling connected No adjustment or calibration is needed Note g Table 1 1 Excelsior Lasers Excelsior Model Power Longitudinal Mode Adjustable Excelsior 473 10 CDRH 10 mW 473 nm single 50 to 100 Excelsior 473 50 CDRH 50 mW 473 nm single 50 to 100 Excelsior 505 20 CDRH 20 mW 505 nm multi 50 to 100 Excelsior 515 50 CDRH 50 mW 515 nm single 50 to 100 Excelsior 532 20M CDRH 20 mW 532 nm multi no Excelsior 532 50 CDRH 50 mW 532 nm single 50 to 100 Excelsior 532 100 CDRH 100 mW 532 nm single 50 to 100 Excelsior 532 150 CDRH 150 mW 532 nm single 50 to 100 Excelsior 532 200 CDRH 200 mW 0532 nm single 50 to 100 Excelsior 532 300 CDRH 300 mW 0532 nm single no Excelsior 542 50 CDRH 50 mW 0542 nm single 50 to 100 Excelsior 561 20 CDRH 20 mW 561 nm single 50 to 100 Excelsior 561 50 CDRH 50 mW 561 nm single 50 to 100 Excelsior 561 100 CDRH 100 mW 561 nm single 50 to 100 Excelsior 561 150 CDRH 150 mW 561 nm single 50 to 100 Excelsior 594 50 CDRH 50 mW 594 nm multi 50 to 100 Excelsior 1064 500 CDRH 500 mW 1064 nm single 50 to 100 Excelsior 1064 800 CDRH 800 mW 1064 nm single 50 to 100 Values are for illustration only refer to Chapter 3 for specified
26. Accordance with Center for Devices and Radiological Health CDRH Regulations eee 2 8 Excelsior Radiation Safety Control Drawings liliis 2 9 Excelsior Warning Labels m re 2 10 Label Translations hh 2 11 Waste Electrical and Electronic Equipment Recycling Label 2 11 Sources for Additional Information 2 12 Laser Safety Standards 0 000 err 2 12 Equipment and Training e I rr 2 13 vii Excelsior Diode Pumped CW Lasers Chapter 3 System Description eer 3 1 A Brief Review of Laser Theory 3 1 Emission and Absorption of Lob 3 1 Population Inversion aa e a a m e ru 3 2 Resonant Optical Cavity and Cavity Modes 2 aaa aaa ia 3 3 Single Longitudinal Mode Operation o oocccccocccncc nenn 3 4 NG asa Laser Medum 5 542 riesgos oa au 3 4 Diode Pumped Laser Design oooococoocc e n 3 5 Frequency Doubling NEEN cee WE PNG ee E eoe RR Rx UY EA NEEN e d 3 7 Ihe Excelsior Lasers oa eder erm EE A any sx a peg 3 8 The Excelsior Laser Head rh 3 8 The Excelsior Power Supply Controller llli ee 3 9 Specifications ceci ii a A re ee ee altius wd edd e 3 10 Outline Drawings a Sit saw RR RES e ru duse uer wie reed eg x aede x KAPPA ahha Se 3 12 Chapter 4 Controls Indicators and Connections 4 1 The Excelsior Laser Head e mh mn 4 1 G ntrOlS cus de tete Pa ac Oe x Tie deis emo Cent Ye Yee
27. Corporation Room A 10F No 80 Sec 1 Jianguo N Rd Zhongshan District Taipai City 104 Taiwan R O C Telephone 886 2 2508 4977 Fax 886 2 2508 0367 Internet sales Onewport com tw United Kingdom Newport Spectra Physics Ltd Registered Office Unit 7 Library Avenue Harwell Science amp Innovation Campus Didcot Oxfordshire OX11 OSG Telephone 44 1235 432710 Fax 44 1235 821045 Internet sales Onewport com uk United States and Export Countries Spectra Physics 3635 Peterson Way Santa Clara CA 95054 2809 Telephone 800 456 2552 Service or 800 SPL LASER Sales or 800 775 5273 Sales or 408 980 4300 Operator Fax 408 980 6921 e mail service spectra physics com sales spectra physics com Internet www spectra physics com And all non European or Middle Eastern countries not included on this list 7 8 Notes Notes 1 Excelsior Diode Pumped CW Lasers Notes 2 Notes Notes 3 Excelsior Diode Pumped CW Lasers
28. Diode Pumped CW Lasers Requirements for Safely Operating the Excelsior Laser with a User Provided Control Device When the Excelsior laser system is controlled by a device provided by the user or by software written by the user the following must be provided e Akeyswitch that limits access to the laser and prevents it from being turned on It can be a real key lock a removable computer disk a pass word that limits access to computer control software or a similar Key implementation The laser must only operate when the key is present and in the on position e An emission indicator that indicates laser energy is present or can be accessed It can be a power on lamp a computer display that flashes a statement to this effect or an indicator on the control equipment for this purpose It need not be marked as an emission indicator so long as its function is obvious Its presence is required on any control panel that affects laser output Schedule of Maintenance in Accordance with Center for Devices and Radiological Health CDRH Regulations 2 8 This laser product complies with Title 21 of the United States Code of Fed eral Regulations Chapter 1 subchapter J parts 1040 10 and 1040 11 as applicable To maintain compliance with these regulations once a year or whenever the product has been subjected to adverse environmental condi tions e g fire flood mechanical shock spilled solvent etc verify
29. E EMISSION m met O O d ob Internal External C Emission Control Switch Enable AC Power Laser Ready AC Power Internal External Indicator Indicator On Off Switch Power Control Switch Remote Safety External Control Interlock Connector Cable Connector FUSE 1A REMOTE Fuse O o e s 100 240V 50 60Hz Figure 2 6 Excelsior Radiation Control Drawings Excelsior Diode Pumped CW Lasers Excelsior Warning Labels VISIBLE AND OR IS EMITTED FROM THIS APERTURE AVOID EXPOSURE Aperture Label CE Aperture Warranty Laser Head 1 Label 2 Seal 3 VISIBLE AND OR INVISIBLE VISIBLE AND OR INVISIBLE LASER RADIATION LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION DIRECT OR SCATTERED RADIATION CLASS 3B LASER PRODUCT CLASS 4 LASER PRODUCT 473 505 515 532 542 561 594 NM WAVELENGTH 1064 NM WAVELENGTH MAXIMUM OUTPUT POWER 500 mW MAXIMUM OUTPUT POWER 1 5 W CE Danger Label 4 S Spectra Physics 3635 Peterson Way Santa Clara CA 95054 MANUFACTURED IN JAPAN MFG P N MONTH YEAR S N COMPLIES WITH 21 CFR 1040 10 AND 1040 11 A150 0110 Serial Number Label 5 Spectra Physics 3635 Peterson Way Santa Clara CA 95054 THIS PRODUCT IS MANUFACTURED UNDER ONE OR MORE OF THE FOLLOWING PATENTS U S
30. Excelsior Diode Pumped CW Lasers User s Manual This laser product complies with performance standards of United States Code of Federal Regulations Title 21 Chapter 1 Food and Drug Administration Department of Health and Human Services SubchapterJ Parts 1040 10 or 1040 11 as applicable G Spectra Physics A Newport Corporation Brand 3635 Peterson Way Santa Clara CA 95054 Part Number 0000 3554 Rev 3 1 June 2010 Preface This manual contains information you need in order to safely install operate and service your Excelsior diode pumped CW laser An Excelsior system consists of one of several models of laser head that produce laser light from 1064 nm to 473 nm along with one of two very similar Excelsior power supplies The power supplies are small stand alone units that provide power control and monitoring functions for the laser Chapter 1 Introduction contains a brief description of the laser system its components and patent information Chapter 2 Laser Safety is required reading before the system is installed and operated Excelsior lasers are Class 3b or Class 4 devices and as such emit laser radiation that can cause permanent eye damage Chapter 2 contains descriptions of these hazards as well as information on how to safeguard against them Included are descriptions of the laser labels and safety devices To minimize the risk of injury or need for expensive repairs be sure to read this chapt
31. Laser is an acronym derived from Light Amplification by Stimulated Emission of Radiation Because the laser is an oscillating amplifier of light and because its output comprises photons that are identical in phase and direction it is unique among light sources Its output beam is singularly directional monochromatic and coherent Radiant emission and absorption take place within the arrangement of the electrons in atoms or molecules Each electron occupies a distinct orbital that represents the probability of finding the electron at a given position relative to the nucleus The energy of an electron is determined by the orbital that it occupies and the over all energy of an atom its energy level depends on the distribution of electrons throughout the available orbitals Each atom has an array of energy levels the level with the lowest possible energy is called the ground state and higher energy levels are called excited states If an atom is in its ground state it will stay there until it is excited by external forces Movement of an electron from one energy level to another a transition happens when the atom either absorbs or emits energy Transitions in both directions can occur as a result of interaction with a photon of light Con sider a transition from a lower level whose energy content is E to a higher one with energy E It will only occur if the energy of the incident photon matches the energy difference between levels i e
32. PATENT NUMBERS E MAM 4 756 003 4 872 177 5 870 415 7 189 703 CE Certification WEEE Patent Label 6 Label 7 Label 8 Figure 2 7 Excelsior Warning Labels 2 10 Label Translations Laser Safety For safety the following translations are provided for non English speak ing personnel The number in parenthesis in the first column corresponds to the label number listed on the previous page Table 2 2 Label Translations Label No French German Spanish Dutch Aperture Ouverture Laser Austritt von sicht Por esta abertura se Vanuit dit apertuur Label Exposition Dange barer und unsicht emite radiaci n l ser wordt zichtbare en 1 reuse Un rayonne barerLaserstrahlung visible e invisible onzichtbare lasers ment laser visible et Bestrahlung ver evite la exposici n traling geemitteerd ou invisible est mis meiden Vermijd blootstelling par cette ouverture CE Rayonnement laser Laserstrahlung Radiaci n l ser Laser straling Danger Exposition Dan Bestrahlung ver Evite la exposici n Vermijd blootstelling Label gereuse Appareil a meiden Producto l ser Clase Klasse 3b laser 4 laser de Classe 3b Laser Klasse 3b 3b produkt Puissance maxi Maximale Aus Potencia m xima Max output ver mum 500 mW gangsleistung 500 mW mogen 500 mW Longueur d onde 500 mW Longitud de onda Golflengtebereik 473 505 515 532 Wellenl nge 473 473 505 515 532 473 505 515 532 542 561 594 nm 505 515 532 542 542
33. R CONTROL switch must be set to INT If the laser power is controlled externally set the PWR CONTROL switch to EXT and provide a stable low noise 5 V signal to Pin 8 of the CONT con nector Do not set the output power level below 50 of the maximum specified out put power for your Excelsior laser model Only the Excelsior lasers listed in Table 6 1 are designed for external power control If your model is suitable only for internal power control verify the PWR CONTROL switch is set to INT Symptom High optical noise Possible Causes Corrective Action Loose cable connector Improper setting for the PWR CONTROL switch Laser is not warmed up Laser head temperature is outside operating range Reflected laser light is desta bilizing the laser Improper ground Vibration is outside operating limits External noise source Verify that all cables are securely connected Verify the PWR CONTROL switch is set to INT If laser power is controlled externally set the PWR CONTROL switch to EXT and provide a stable low noise 5 V signal to Pin 8 of the CONT con nector Allow the laser to warm up for at least 5 minutes Measure the temperature of the baseplate If it is below 10 C or exceeds 50 C or 45 C for Group B models verify the ambient temperature is within the allowable operating range and correct if necessary Refer to Table 5 1 Figure 5 1 and Figure 5 2 Verify the laser head baseplate is prop
34. Tables Table 1 1 Excelsior Lasers viii a aie a PI Re Br De E 1 2 Table 1 2 Excelsior Power Supply Controllers 1 2 Table 2 1 Maximum Emission Levels 2 7 Excelsior Diode Pumped CW Lasers Table 2 2 Table 4 1 Table 5 1 Table 5 2 Table 5 3 Table 6 1 Table 6 2 Table 7 1 Label Translations 242420 ee eat da PROD NAAN 2 11 External Control CONT Connector Pin Functions esses 4 5 Heat Dissipation Laser Head 5 2 Lasers capable of variable output power 5 4 External Control CONT Connector Pin Functions 0000 lessen 5 5 Lasers capable of variable output power 6 4 Recommended Parameters for R and VR in Figure ph 6 5 Replacement Parts zs eer rn fe RAN aust a EE ae dG clei gs 7 5 Warning Conventions The following warnings are used throughout this manual to draw your attention to situations or procedures that require extra attention They warn of hazards to your health damage to equipment sensitive procedures and exceptional circumstances All messages are set apart by a thin line above and below the text as shown here Danger Laser radiation is present Laser Radiation Danger Danger Warning Warning ESD Caution Don t Touch Eyewear Required Y by Ur y U E A Condition or action may present a hazard to personal safety Condition or action may present an electrical hazard to personal safety Condition or action may cause da
35. al N N For transition between two lev els N can never exceed N because every upward transition is matched by one in the opposite direction However if three or more energy levels are involved in the transition a population inversion can occur where N gt N A model four level laser transition scheme is depicted in Figure 3 1 A photon of frequency v excites or pumps an atom from E to E If the E to E transition probability is greater than that of E to E and if the life time of an atom at E is short the atom will decay almost immediately to E If E is metastable 1 e electrons occupy it for a relatively long time the population will grow rapidly as excited electrons cascade from above The E electron will eventually decay to E emitting a photon of frequency v Finally if E is unstable its electrons will rapidly return to the ground state E keeping the population of E small and reducing the rate of absorption of v In this way the population of E is kept large and that of E remains low thus establishing a population inversion between E and E Under these conditions light is amplified as it passes through the material which is now a gain medium E4 A V2 vi E1 Figure 3 1 A Typical Four level Transition Scheme System Description Resonant Optical Cavity and Cavity Modes Most laser materials must be placed in a resonant optical cavity to achieve useful levels of amplified
36. all features of the product identified on the Excelsior CDRH Radiation Con trol Drawing Figure 2 6 on page page 2 9 function properly Also make sure that all warning labels remain firmly attached 1 Verify that opening any safety interlock switch used with the system prevents laser operation 2 Verify the laser can only be turned on when the EMISSION keyswitch is in the ON position and that the key can only be removed when the switch is in the STBY position 3 Verify the EMISSION indicator s provides a visible signal when the laser emits accessible laser radiation that exceeds the accessible master system emission limits for Class I 4 Verify the time delay between turn on of the EMISSION indicator s and the start of laser emission it must give enough warning to allow action to avoid exposure to laser radiation 5 Verify the mechanical shutter closes and actually blocks laser radia tion emission If any of the above items fail to operate as noted and you cannot correct the error please call your Spectra Physics service representative for assistance 0 39 uW for continuous wave operation where output is limited from 400 nm to 1400 nm Laser Safety Excelsior Radiation Safety Control Drawings Refer to the warning labels on page 2 10 Laser beam Emission Emission Indicator On Off Keyswitch yA NEM S POWER ENABLE STABLE SERVIC
37. ating range The shutter can be opened at this time Refer to Using the External Stable Signal Pin 1 on page 6 3 Laser ON OFF When this pin is shorted to ground the laser will turn on fol lowing a 3 to 5 second delay Refer to Turning the Laser On and Off Pin 2 on page 6 2 for instructions Laser ENABLE This pin becomes internally shorted to ground through a transistor when laser head temperature is within the proper operating range The laser may be turned on at this time Refer to Using the External Enable Signal Pin 3 on page 6 3 for instructions Current Monitor This pin provides an output signal proportional to the current of the diode pump laser The scale is 100 mV Amp and maximum signal is 160 mV corresponding to 1 6 A Laser Power Monitor This pin provides an output signal that is approximately pro portional to the power output of the laser Actual signal level depends on the laser model When nominal power 10096 is emitted from the laser the voltage on Pin 5 is about 100 mV typically 96 to 98 mV Example a Pin 5 signal of 50 mV for the Excelsior 532 150 indicates that laser power is about 75 mW 4 5 Excelsior Diode Pumped CW Lasers Table 4 1 External Control CONT Connector Pin Functions Pin Type Description Function 8 Input External Power Control This pin is used to vary the output power of the lasers listed in Table 6 1 Refer to Changing Laser Output Power Pin 8 on page 6
38. ation in this document is subject to change without Excelsior Diode Pumped CW Lasers notice Spectra Physics makes no representation or warranty either express or implied with respect to this document In no event will Spectra Physics be liable for any direct indirect special incidental or consequential damages resulting from any defects in this documentation Finally if you encounter any difficulty with the content or style of this manual or encounter problems with the laser itself please let us know At the end of this manual is a form to aid in bringing such problems to our attention Thank you for your purchase of Spectra Physics instruments Environmental Specifications CE Electrical Equipment Requirements For information regarding the equipment needed to provide the electrical service requirements listed in Specifications on page 3 10 please refer to specification EN 309 Plug Outlet and Socket Couplers for Industrial Uses listed in the official Journal of the European Communities Environmental Specifications The environmental conditions under which the laser system will function are listed below Indoor use Vibration lt 1 5 m s 0 15 G 15 Hz 200 Hz Laser Head Temperature 10 C to 40 C Maximum relative humidity lt 80 non condensing over the allowed temperature range Insulation category II Pollution degree 2 Table of Contents Preface ece A E A en iii Environmental Specific
39. ations AA ees V CE Electrical Equipment Requirements ren V Environmental Specifications 0 2 20 0 ccc hne V Warning Conventions vir RARA xi Standard UNES cias a RA Sik Bw Ran SRA xiii Unpacking and Inspection ooooooccrcncnn eee XV Unpacking Your Laser XV System Components o XV ACCESSONIGS c d Beet S a Salto Haus E OE US EA A A ehe XV Chapter 1 Introduction 4 coo ee eels eee a a gees 1 1 General Information uns ome ted Mes a med oe dal ea dead ann Vote BUR pen 1 1 Patents sta 2a AP da a acca ucts pe wt e ARA NAH 1 3 Ghapter 2 Laser Safety sota ein 2 1 General Elazards uti em Reate e eh x do Ee ded e gy EC PRU woe EE o PAL PUY e etat god 2 1 Precautions for the Safe Operation of Class Illb High Power Lasers 2 2 Safety Devices 2 3 On Off AC Power Switch crus A sure ware p Nai e EAR a 2 4 AG Power INdICAtOR wa e gue recor wage pe y ego nde a E UR en sede 2 4 Enable Indicator hh 2 5 Emission Keyswitch e hr 2 5 Stable Indicator adu recep EEN uU a EH EAR Sele Te SU eter wr DLA 2 5 Emission Indicator ER NALANG Cedo A HAL ARR ege Rn 2 5 Internal External Emission Control Switch eee 2 6 Internal External Power Control Switch 0 0 aaa aaa e 2 6 Safety Interlocks eier Add RW RE Ede IP EY Re EE 2 6 Maximum Emission Level 2 7 Requirements for Safely Operating the Excelsior Laser with a User Provided Control Device 2 8 Schedule of Maintenance in
40. ator mirrors Such coatings transmit a high percentage of any 1064 nm light that might be present thus decreasing the rate of stimulated emission for this wavelength and allowing the 946 nm transition to lase The 946 nm transition is referred to as quasi three level because the lower laser level lies so close to the 19 ground state Despite this small difference in energy the lower laser level still empties quickly enough to allow CW operation for this wavelength However the small difference in energy from the ground state does mean that the material will self absorb at the lasing wavelength Self absorption is a parasitic effect in which the laser light is absorbed by the laser crystal itself The lower laser level for the quasi three level transi tion in vanadate is significantly populated by electrons thermally excited from the ground state resulting in absorption of the 946 nm light as the electrons then make the reverse transition to the upper laser level Nd Y AG exhibits the same effect but thermal population of the lower laser level is less so the blue Excelsior lasers employ YAG crystals to produce the 946 nm wavelength for doubling to 473 nm Self absorption can also be reduced somewhat by carefully engineering the diode pump design Diode Pumped Laser Design Diode lasers combine very high brightness high efficiency monochroma ticity and compact size in a near ideal source for pumping solid state lasers Figure 3 4
41. celsior 50 mW 515 nm single mode Excelsior 20 mW 532 nm multi mode Excelsior 50 mW 532 nm single mode Excelsior 100 mW 532 nm single mode Excelsior 150 mW 532 nm single mode Excelsior 200 mW 532 nm single mode Excelsior 300 mW 532 nm single mode Excelsior 25 mW 561 nm single mode Excelsior 50 mW 561 nm single mode Excelsior 100 mW 561 nm single mode Excelsior 150 mW 561 nm single mode Excelsior 50 mW 594 nm multi mode Excelsior 500 mW 1064 nm single mode Excelsior 800 mW 1064 nm single mode Excelsior Power Supply for standard laser heads Excelsior Power Supply for extended cavity XC laser heads Excelsior Laser Head Cable for standard laser 1 8 m 6 ft Excelsior Laser Head Cable for extended cavity laser 1 8 m 6 ft Excelsior Remote Connector Excelsior Power Supply Emission Key Excelsior 473 10 SLM CDRH Excelsior 473 50 SLM CDRH Excelsior 505 20 MLM CDRH Excelsior 515 50 SLM CDRH Excelsior 532 20 MLM CDRH Excelsior 532 50 SLM CDRH Excelsior 532 100 SLM CDRH Excelsior 532 150 SLM CDRH Excelsior 532 200 SLM CDRH Excelsior 532 300 SLM CDRH Excelsior 561 25 SLM CDRH Excelsior 561 50 SLM CDRH Excelsior 561 100 SLM CDRH Excelsior 561 150 SLM CDRH Excelsior 594 50 MLM CDRH Excelsior 1064 500 SLM CDRH Excelsior 1064 800 SLM CDRH Excelsior PS CDRH Excelsior PS XC CDRH Excelsior Laser Cable CDRH Excelsior Laser Cable XC CDRH Excelsior Connector CDRH Excelsior Key CDRH
42. celsior Power Supply Safety Devices On Off AC Power Switch AC Power Indicator Turning on the POWER rocker switch activates the power supply circuitry as indicated by the white POWER indicator on the front panel Activating this switch begins the process of warming the laser head components to operating temperature which typically takes between 2 and 5 minutes This indicator turns on when the ac power is turned on Enable Indicator Emission Keyswitch Stable Indicator Emission Indicator Laser Safety When the laser head components have warmed to their operating tempera ture following turning on the POWER switch this indicator glows steadily The laser is now ready to operate The keyswitch provides interlock safety to prevent unauthorized personnel from using the laser when the key is turned to the STBY position and removed If the POWER switch has been turned on and the ENABLE indicator is on and the EMISSION CONTROL switch has been set to INT turning on the EMISSION keyswitch will turn on the laser following a safety delay of 3 to 5 seconds If the shutter is open the laser will emit a laser beam Optionally if the EMISSION CONTROL switch has been set to EXT the Excelsior laser can be turned on when a suitable control signal is applied to Pin 2 of the CONTrol connector on the back of the power supply See Chapter 6 for details of this method of operation This indicator turns on when laser power reaches its se
43. celsior power supply The safety circuit of the Excelsior accessed through the 2 pin REMOTE connector on the back of the power supply must be closed in order for the laser to operate An interlock jumper plug Figure 3 6 is provided with the system to allow the laser to operate when an optional interlock safety switch e g a switch across a laboratory door is not employed Figure 3 6 REMOTE Interlock Jumper Plug The power supply contains two main components a switching power sup ply and a control pc board The switching power supply provides 5 Vdc to the control pc board with a maximum drive current of 5 A or 8 A depend ing on model The control pc board supplies low noise regulated DC cur rent to the laser head to drive the diode laser and a thermo electric cooler 3 9 Excelsior Diode Pumped CW Lasers Specifications This page and the next one are to be discarded and replaced with the 11 x 17 Specifications fold out page 3 10 System Description Excelsior Diode Pumped CW Lasers Outline Drawings 4 3 L gt 110 0 4 3 4 gt e gt 11 87 alle D EE J 11 17 F TI 28 42 Beam Exit Se N N C Aperture Beam Height 0 75 ME 19 022 1 44 E 5 5 36 5 TE Y A p 4 3 Dimensions given in ng 110 inches 101 gt mm 3 7 93 gt 2 0 50 03 Hm Wx4L 4 R2
44. ction of the doubled light out of the resonator while confining the rest of the doubled light and virtually all of the infrared beam inside the laser head The infrared pump power of the diode laser is mode matched in the laser crystal This together with the design of the resonator optics results in TEM output The lasers also operate in single longitudinal mode except for the lowest power green model which has multiple longitudinal mode output refer to the tables of specifications at the end of this chapter Single longitudinal mode operation is achieved by inserting an etalon in the intracavity space to broaden the spacing of the longitudinal modes beyond the bandwidth of the laser gain so that only one mode at a time fits within the gain spectrum The Excelsior laser head includes an output telescope assembly that expands and collimates the beam before it exits the laser head Refer to the tables of specifications for exact details Some models of the Excelsior produced for integration into the optical train of an OEM master system are available without collimation If interested contact Spectra Physics for additional information All models of the Excelsior include an internal detector to measure output power The detector is part of a servo loop that maintains constant laser output power over the lifetime of the device by adjusting the current of the diode pump laser System Description Mechanical and Thermal Design The la
45. d removed If the POWER switch has been turned on and the ENABLE indicator is on and the EMISSION CONTROL switch has been set to INT turning on the EMISSION keyswitch will turn on the laser following a safety delay of 3 to 5 seconds If the shutter is open the laser will emit a laser beam Optionally if the EMISSION CONTROL switch has been set to EXT the Excelsior laser can be turned on by applying a suitable control signal to Pin 2 of the CONTrol connector on the back of the power supply However the POWER switch must already be on and EMISSION keyswitch must be in the STBY position prior to sending the On signal See Chapter 6 for details of this method of operation Controls Indicators and Connections POWER ON OFF switch turns on power to the power supply When switched on and the internal circuits respond properly the POWER indica tor on the front panel turns on Once on the laser head resonator begins to warm to its operating temperature which typically takes between 2 to 5 minutes The ENABLE indicator turns on when warm up is complete Indicators POWER indicator turns on when the POWER switch is turned on and the internal circuits respond properly ENABLE indicator turns on when the laser resonator has warmed to its operating temperature which is about 2 to 5 minutes after the POWER switch has been turned on Once this light is on the laser can be turned on STABLE indicator turns on when laser power reac
46. described in the preceding section Refer to the outline drawings at the end of Chapter 3 for mounting hole locations Holes and slots are provided for precision alignment pins Note that slots are provided only on Excelsior DPSS CDRH lasers Position the laser head in the desired location then use four M3 or 4 40 screws and washers to mount the laser head using the mounting holes slots on the front and back of the baseplate or use four smaller screws and washers to use the slots on the sides of the baseplate The boresight specifications are with respect to the axis of the precision alignment hole and slot Note that the beam height is located 19 mm about 34 in above the baseplate mounting surface The heatsink surface for the laser head must be flat to 0 050 mm or better The laser head can withstand a small amount of vibration and still perform to specification Refer to the specifications listed at the end of Chapter 3 for more information Mounting the Power Supply The power supply is a standard table top device Refer to the outline draw ing in Figure 3 9 on page 3 14 Connecting the Cables 1 Connect the 1 8 m 6 ft laser head cable provided between the con nector on the laser head and the LASER connector on the back of the power supply 2 If desired wire a remote safety switch or series of switches to the 2 pin REMOTE connector on the back of the power supply These 2 pins must be shorted in order for the laser
47. ensure proper installa tion and safe operation of your laser Safety Devices Figure 2 3 and Figure 2 4 on the next page show the locations of the safety devices on the laser head and power supply The laser head includes a manually operated shutter All control and moni toring of the laser is through the power supply or optionally through the CONTrol connector on the power supply back panel Shutter vi Laser Beam ae O LL BG Figure 2 3 Laser Head Manual Shutter in compliance with CDRH Standards the laser head must be operated using the 1 8 meter laser control cable provided with the system When connected to the power supply this cable keeps the laser head within the CDRH specified distance from the emission indicator located on the power supply front panel Note al There is no emission indicator on the laser head itself In order to remain 2 3 Excelsior Diode Pumped CW Lasers Enable Laser Ready Emission Internal External Internal External Indicator Indicator Emission Control Switch Power Control Switch EMISSION ABLE STABLE SERVICE O AC Power Indicator AC Power On Off Switch Emission On Off Keyswitch Laser Power Stable Indicator External Control Cable Connector Remote Safety Fuse Interlock Connector Figure 2 4 Ex
48. eplacement Pas cocos A Pals eee A mE trn Geta dE SEN 7 5 viii Table of Contents Gustomer Service eet Peas as eae odes a pe nd b eds 7 6 Matten Geier Sgt bee a wean dt as 7 6 Returning the Instrument for Repair 7 6 Service Genlets irc a a en Da ae ale dE a ng RG AEA ae NAUNA 7 7 Notes Report Form for Problems and Solutions List of Figures Figure 1 1 The Standard DPSS Excelsior Laser Head 1 1 Figure 2 1 These standard safety warning labels are appropriate for use as entry warning signs EN 60825 1 2007 ANSI Z136 1 Section 4 7 2 0 s 2 2 Figure 2 2 Folded Metal Beam Target 2 2 Figure 2 3 Laser Head Manual Shutter 2 3 Figure 2 4 Excelsior Power Supply Safety Devices cece tees 2 4 Figure 2 5 Remote Interlock Jumper Plug ooooococcoco eee 2 6 Figure 2 6 Excelsior Radiation Control Drawings 2 9 Figure 2 7 Excelsior Warning Labels 2 10 Figure 3 1 A Typical Four level Transition Scheme 3 2 Figure 3 2 Frequency Distribution of Longitudinal Modes 2 2 22en eee eee 3 3 Figure 3 3 Energy Level Scheme for the Nd lon in YAG LLuuaaaaa aaa aa aaa eee 3 4 Figure 3 4 Nd absorption spectra compared to emission spectra of a Black Body Source a and a Diode Laser Onda ie DEE a ictu Mb c ee Dich ee ss 3 6 Figure 3 5 Mode Matching arai es iera tikt eia e m un 3 6 Figure 3 6 Remote Interlock Jumper Plug III 3 9 Figure 3 7 Outline Drawing of the Excels
49. er and carefully follow its instructions H Chapter 3 Laser Description contains a short section on laser theory regarding the principles used in the Excelsior laser The theory section is followed by a more detailed description of the Excelsior laser and concludes with specifications for the various Excelsior models Chapter 4 Controls Indicators and Connections describes the various features of the system Chapter 5 Installation describes the procedures and requirements for installing the laser and power supply controller Chapter 6 Operation describes methods of operating the laser using the power supply by itself or optionally using analog signals provided through the power supply interface to operate it remotely Chapter 7 Troubleshooting and Service will help guide you to the source of any problems with the laser Do not attempt repairs yourself while the unit is still under warranty instead report all problems to Spectra Physics for warranty repair The Customer Service section in Chapter7 provides information regarding service calls and warranty issues Should you experience any problems with the your Excelsior laser or if you are in need of technical information or support on any issues related to its use refer to the list of world wide Spectra Physics service centers in this section Every effort has been made to ensure that the information in this manual is accurate All inform
50. er to stabilize Once stabilized the STABLE indicator will illuminate 5 Open the shutter to unblock the laser output beam To turn the laser off turn the EMISSION keyswitch to STBY remove the key and close the shutter This is the recommended off condition when the laser is going to be used frequently it saves warm up time If the laser is not to be used for an extended period e g when turned off over night also turn off the ac POWER switch or utility power Operating the Laser Using the External Control Interface All laser functions can be controlled by applying remote analog signals to the CONTrol interface connector on the back of the power supply Table 5 3 on page 5 5 defines the function of each pin of that connector Note that ground pins for the CONTrol connector are Pins 6 7 10 and 11 Before using a remote source to control the laser the EMISSION CONTROL switch on the side of the power supply must be set to EXT Figure 4 7 Then leaving the EMISSION keyswitch set to STBY apply ac power to the power supply and turn on the POWER switch The following discussions assume that this has already been done To return the system to internal control and maximum output power set the EMISSION CONTROL switch back to INT Turning the Laser On and Off Pin 2 The laser can only be turned on after the resonator has reached normal oper ating temperature and the ENABLE signal Pin 3 is pulled low see Using the Ex
51. erly heat sinked Ensure that light reflected from any external optical elements does not reflect back through the window of the laser head Check the grounding of the laser head and the power supply Verify any vibration experienced by the laser head is within operating limits Verify that there are no strong electromagnetic noise sources near the sys tem If output power is controlled externally verify the voltage signal applied to Pin 8 of the CONT connector is low noise Symptom Bad transverse mode Possible Causes Corrective Action Improper setting for the PWR CONTROL switch Laser is not warmed up Dirty output window Verify the PWR CONTROL switch is set to INT If the laser power is controlled externally set the PWR CONTROL switch to EXT and provide a stable low noise 5 V signal to Pin 8 of the CONT con nector Allow the laser to warm up for at least 5 minutes Clean the laser head output window 7 3 Excelsior Diode Pumped CW Lasers Symptom Bad transverse mode Laser head temperature is Measure the temperature of the baseplate If it is below 10 C or exceeds outside operating range 50 C or 45 C for Group B models verify the ambient temperature is within the allowable operating range and correct if necessary Refer to Table 5 1 Figure 5 1 and Figure 5 2 Verify the laser head baseplate is properly heat sinked Reflected laser light is desta Ensure that light reflected from any external
52. gure 4 7 The Power Supply Side Panel Controls Indicators and Connections PWR CONT switch allows Excelsior output power to be controlled remotely Refer to the description of the CONTrol connector on page 4 5 above and Changing Laser Output Power Pin 8 on page 6 4 EMISSION CONT switch allows the Excelsior laser to be turned on and off remotely via Pin 2 of the CONTrol connector Refer to the CONTrol con nector on page 4 5 and Turning the Laser On and Off Pin 2 on page 6 2 4 7 Excelsior Diode Pumped CW Lasers 4 8 Chapter 5 Power Installation Detailed descriptions of the signals and connectors for the Excelsior laser system are provided in Chapter 4 Controls Indicators and Connections Examples of how to operate the laser using either the controls on the power supply controller itself or via external signals applied to the CONTrol inter face connector on the power supply are given in Chapter 6 Operation A control cable provides control power monitoring and diagnostic signals between the laser head and the power supply Depending on the system either a 15 pin to 15 pin cable is provided Standard CDRH systems or a 26 pin to 26 pin cable is provided XC CDRH systems The cable is attached between the LASER connector on the back of the power supply and the connector on the laser head If external control is desired the user must provide a cable with a 15 pin D sub connector on one end for
53. he housing as long as the ambient temperature meets the following specifications 5 1 Excelsior Diode Pumped CW Lasers Ambient temperature operating Baseplate of laser head operating Table 5 1 Heat Dissipation Laser Head 10 C 40 C lt 80 RH for the power supply and laser head 10 C 50 C for the laser head belonging to Groups A and C 10 C 45 C for the laser head belonging to Group B Standard Laser Head XC Laser Head Group A Group B Group C Excelsior 473 10 CDRH Excelsior 532 50 100 CDRH Excelsior 532 20M CDRH Excelsior 473 50 CDRH Excelsior 532 150 200 CDRH Excelsior 542 50 CDRH Excelsior 561 20 50 75 CDRH Excelsior 1064 500 800 CDRH Excelsior 505 20 CDRH Excelsior 515 50 CDRH Excelsior 532 300 CDRH Excelsior 561 100 150 CDRH Excelsior 594 30 50 CDRH 0 L L 10 e a UE 30 z C 5 25 77 a 20 a 5 15 g B A o Ku Q E o T 0 10 20 30 40 50 60 70 Laser Head Baseplate Temperature Operational C Figure 5 1 Heat Dissipation of the Laser Head co Maximum Permissible Heatsink Thermal Impedance C W IN 0 L L 0 10 20 30 40 50 60 Ambient Temperature C Figure 5 2 Maximum Permissible Heatsink Thermal Impedance Installation Installing the Hardware Mounting the Laser Head Follow standard practice to mount the laser head on a suitable heatsink that meets the requirements
54. hes its set value and becomes stable and it remains on as long as laser power is stable The laser typically reaches its set operating power and becomes stable about 10 sec onds DPSS CDRH or 30 seconds DPSS XC CDRH after turning on the EMISSION keyswitch or after an On command has been received at Pin 2 of the CONTrol interface connector SERVICE indicator turns on when diode laser current rises to 95 of the factory set current limit This indicates that a replacement laser head is needed although not immediately Laser emission will be stable until the current reaches the 10096 limit When the limit is exceeded emission will continue but power may decrease and or fluctuate EMISSION indicator turns on when the EMISSION keyswitch is turned on see the prerequisites for turning on the keyswitch above and emission occurs 3 to 5 seconds later Note this indicator does not blink during the delay as it does on some other laser systems If the REMOTE interlock circuit is opened see the description below laser emission stops immediately and this indicator turns off If the REMOTE interlock switch is then closed again one of the following actions occur e Ona standard Class 3b laser or extended cavity XC laser if the key switch is still in the ON position the EMISSION indicator turns on again immediately and the laser turns on again following a safety delay of 3 to 5 seconds e Ona standard Class 4 laser if the keyswitch
55. igure 2 5 REMOTE Interlock Jumper Plug Cover Safety Interlocks Do not open the Excelsior laser head or power supply covers The system is not designed to be operated with its covers removed Therefore the units do not have cover safety interlocks When the diode pump laser in the Excelsior head requires replacement the entire laser head is replaced as a unit Before starting any replacement pro cedure the power supply must be disconnected from the AC outlet Laser Safety Maximum Emission Levels The following are the maximum emission levels possible for the different Excelsior laser systems Use this information for selecting appropriate laser safety eyewear and implementing appropriate safety procedures These values do not imply actual system specifications Table 2 1 Maximum Emission Levels Emission Wavelength Design Power Maximum Output Power 808 nm Diode 0 1W 473 nm Laser Head 10 mW 0 1W 473 nm Laser Head 50 mW 0 1W 505 nm Laser Head 20 mW 0 1W 515 nm Laser Head 50 mW 0 3 W 532 nm Laser Head 20 mW 0 5 W 532 nm Laser Head 50 mW 0 5 W 532 nm Laser Head 100 mw 0 5 W 532 nm Laser Head 150 mW 0 5 W 532 nm Laser Head 200 mW 0 5 W 532 nm Laser Head 300 mW 0 5 W 542 nm Laser Head 50 mW 0 3 W 561 nm Laser Head 25 mW 0 2 W 561 nm Laser Head 50 mW 0 2 W 561 nm Laser Head 100 mw 0 3 W 561 nm Laser Head 150 mW 0 3 W 594 nm Laser Head 50 mW 0 3 W 1064 nm Laser Head 500 mW 1 5W 1064 nm Laser Head 800 mW 1 5W Excelsior
56. in 5 signal of 50 mV for the Excelsior 473 10 CDRH indicates that laser power has fallen to about 5 mW Excelsior PS XC CDRH At full output power the signal is approxi mately 2 V In order to avoid affecting the automatic power control circuit inside the controller the input impedance of the external circuit should be greater than 10 KQO preferably greater than 100 KQO Using the 12 Vdc Output Pin 9 Pin 9 provides a 12 Vdc source that can be used with Pin 8 to vary laser output power see Changing Laser Output Power Pin 8 on page 6 4 Figure 6 6 shows a schematic of the 12 Vdc circuit The impedance Zour of the external user circuit must not draw more than 20 mA total from Pin 9 5Vor12V 12V From external DC power supply or built in DC DC converter DC power supply Output Impedance Zout Gnd External Circuit Power Supply Figure 6 6 The 12 Vdc Supply Circuit Using the Thermistor Alarm Pin 13 A thermistor inside the laser head is used as part of a circuit to control the temperature of the laser resonator When an open thermistor occurs such as when a wire breaks on the thermistor from shock and or vibration the thermistor alarm is activated on Pin 13 the pin goes low When this alarm occurs temperature control and laser emission are terminated Fig ure 6 7 shows an example circuit The Pin 13 transistor can sink up to 20 mA maximum Operation Thermistor Alam I Thermistor I
57. ior DPSS CDRH Laser Head 3 12 Figure 3 8 Outline Drawing of the Excelsior DPSS XC CDRH Laser Head 3 13 Figure 3 9 Outline Drawing of Excelsior Power Supply Controller 3 14 Figure 4 1 The Standard Excelsior Laser Head 2 teen eee 4 1 Figure 4 2 Shutter Open Close Designations 4 1 Figure 4 3 The Power Supply Controller Front Panel 4 2 Figure 4 4 The Power Supply Controller Back Panel 4 4 Figure 4 5 Remote Interlock Jumper Plug aaa IIR 4 4 Figure 4 6 External Control Connector Pin Numbering 2 42 aaa aaa aaa ai 4 5 Figure 4 7 The Power Supply Side Panel aaa ren 4 6 Figure 5 1 Heat Dissipation of the Laser Head eee 5 2 Figure 5 2 Maximum Permissible Heatsink Thermal Impedance 5 2 Figure 5 3 Remote Connector Jumper Plug 5 3 Figure 5 4 External CONTrol Interface Connector Pin Numbering seers 5 4 Figure 6 1 Example of a typical laser On Off control circuit 6 2 Figure 6 2 Example Circuit for a Remote Enable Signal Indicator 6 3 Figure 6 3 Example Circuit for a Remote Stable Emission Signal Indicator 6 3 Figure 6 4 Example or a Service Alarm Coup 6 4 Figure 6 5 Example Circuits for Varying Laser Output Power 6 5 Figure 6 6 The 12 Vdc Supply Circuit llli 6 6 Figure 6 7 Thermistor Alarm Example Crount eee 6 7 Figure 6 8 Remote Interlock Jumper Plug 6 7 List of
58. ior lasers are designed for hands off operation This product does not require alignment nor routine cleaning of cavity optics Service is generally limited to replacing the entire laser head Spectra Physics offers service training programs to train personnel in diagnosing problems Troubleshooting This troubleshooting guide is intended to assist you in identifying some of the problems that might arise while using the system For information about repairing the laser please call your Spectra Physics representative A list of world wide service sites 1s included at the end of this chapter Symptom No laser beam Possible Causes Corrective Action Shutter is closed Verify the hand operated shutter is open set to the left Loose cable connector Verify that all cables are securely connected Improper settings for the If laser is controlled internally both the PWR CONTROL and the EMIS internal external control SION CONTROL switches must be set to INT switches External control No On signal applied to the If laser power is controlled externally the EMISSION CONTROL switch CONT connector must be set to EXT Pin 2 of the CONT connector must be pulled to ground to turn on the laser Improper settings for exter If laser power is controlled externally the PWR CONTROL switch must be nal power control set to EXT The ac POWER switch and the EMISSION keyswitch must both be on Pin 8 of the CONT connector must receive a suitable inp
59. is dis abled for the first 5 minutes after the EMISSION keyswitch is turned on Service Alarm O 5V Service Alarm Indicator Service Alarm Signal active low Gnd O Gnd I Power Supply l External Circuit Figure 6 4 Example or a Service Alarm Circuit Changing Laser Output Power Pin 8 Caution W 6 4 The output power of the lasers listed in Table 6 1 can be varied from 50 to 100 by varying the voltage on Pin 8 from 0 to 5 V To implement this the PWR CONTROL switch located on the side of the power supply Figure 4 7 must first be set to EXT Be sure the PWR CONTROL switch is set to INT for Excelsior models NOT listed in Table 6 1 those lasers will not operate if this switch is mistakenly set to EXT Table 6 1 Lasers capable of variable output power Excelsior A73 10 Excelsior 542 50 Excelsior 473 50 Excelsior 561 25 Excelsior 505 20 Excelsior 561 50 Excelsior 515 50 Excelsior 561 100 Excelsior 532M 20 Excelsior 561 150 Excelsior 532 50 Excelsior 594 50 Excelsior 532 100 Excelsior 1064 500 Excelsior 532 150 Excelsior 1064 800 Excelsior 532 200 These lasers will only operate at constant full power when the PWR CONTROL switch is set to INT 2 These lasers meet specified parameters only at 100 laser output power Operation The full set of Excelsior specifications are guaranteed only at the 100 Note zl Operating the laser below 50 of its rated power is not recommended
60. itself called intracavity frequency dou bling to take advantage of the high circulating intensity This is the opti cal design used in the Excelsior 3 7 Excelsior Diode Pumped CW Lasers The Excelsior Lasers Table 1 1 and Table 1 2 list the various Excelsior laser models The power supply controller provides electrical power control and monitoring signals to the laser head Output power on most Excelsior lasers models can be varied from 50 to 100 using an external control signal connected to an interface on the power supply A few however are design for operation at constant power only The Excelsior Laser Head 3 8 Note The Excelsior laser head provides maximum reliability with minimum complexity and size The inherent operation is so stable and the output so quiet that no adjustments are needed for normal operation Laser Cavity Design The Excelsior uses a compact linear cavity for convenient end pumping of the laser crystal The diode pump laser in the Excelsior laser head is sometimes referred to simply as the diode in this manual e g the diode current The infrared light generated by the laser crystal is intracavity frequency doubled to produce either green or blue output that is the output of a van adate crystal at 1064 nm is doubled to 532 nm in the green lasers and the output of a YAG crystal at 946 nm is doubled to 473 nm in the blue laser A dichroic output coupler transmits a fra
61. ive eyewear is available from suppli ers listed in the Laser Focus World Lasers and Optronics and Photo nics Spectra buyer s guides Consult the ANSI and ACGIH standards listed at the end of this section for guidance e Maintain a high ambient light level in the laser operation area so the eye s pupil remains constricted reducing the possibility of damage e To avoid unnecessary radiation exposure keep the protective cover on the laser head at all times e Avoid looking at the output beam diffuse reflections are hazardous e Establish a controlled access area for laser operation Limit access to those trained in the principles of laser safety e Enclose beam paths wherever possible e Post prominent warning signs near the laser operating area Figure 2 1 e Install the laser so that the beam is either above or below eye level e Set up shields to prevent any unnecessary specular reflections or beams from escaping the laser operation area e Set up a beam dump to capture the laser beam and prevent accidental exposure Figure 2 2 VISIBLE AND OR INVISIBLE LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION VISIBLE AND OR INVISIBLE LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION 473 505 515 532 542 561 584 NM WAVELENGTH MAXIMUM OUTPUT POWER 500 mW CLASS Illb LASER PRODUCT CLASS 4 LASER PRODUCT 1064 NM WAVELENGTH MAXIMUM OUTPUT POWER 1 5 W
62. l and electronic equipment WEEE In accordance with this directive the accompanying product has been marked with the WEEE symbol See Label 7 on page 2 10 The purpose of the symbol is to designate that at the end of its useful life the accompanying product should not be disposed of as normal municipal waste but should instead be transported to a collection facility that will ensure the proper recovery and recycling of the product s components The symbol also signifies that this product was placed on the market after 13 August 2005 At this time regulations for the disposal of waste electri cal and electronic equipment vary within the member states of the Euro pean Union Please contact a Newport Spectra Physics representative for information concerning the proper disposal of this product Laser Safety Sources for Additional Information Laser Safety Standards Safe Use of Lasers Z136 1 American National Standards Institute ANSI 25 West 43 Street 4 Floor New York NY 10036 Tel 212 642 4900 Occupational Safety and Health Administration Osha Standard 01 05 001 pub8 1 7 U S Department of Labor 200 Constitution Avenue N W Room N3647 Washington DC 20210 Tel 202 693 1999 Internet http www osha gov A Guide for Control of Laser Hazards 4th Edition Publication 0165 American Conference of Governmental and Industrial Hygienists ACGIH 1330 Kemper Meadow Drive Cincinnati OH 45240 Tel 513
63. le of a circuit used for this purpose Excelsior Diode Pumped CW Lasers Internal External Emission Control Switch This slide switch provides the option to turn the laser on and off by means of the EMISSION keyswitch or via a signal applied to Pin 2 on the CONTrol connector on the back of the power supply See Chapter 6 for details on how to use this option Internal External Power Control Switch Safety Interlocks The PWR CONTROL switch when set to EXT is used to enable external control of laser output power for all Excelsior lasers When set to INT out put is at full power INT is also the required setting for operating the lower power Excelsior lasers Output power is controlled externally by means of an analog signal applied to Pin 8 of the CONTrol connector on the back of the power supply See Chapter 6 for details on how to use this option Safety Interlock The 2 pin REMOTE interlock connector on the back of the power supply can be wired to one or more external normally closed safety switches all wired in series to stop laser emission in the event any one of these switches is opened Such a switch is typically attached to a laboratory door or criti cal access point so that the switch opens when the door is opened thus turning off the laser To ensure that the laser can operate when this interlock is not used the sys tem is shipped with a shorting jumper plug Figure 2 5 that closes the interlock control loop F
64. light This cavity is typically two mirrors placed facing each other to form a resonator that reflects light back and forth through the gain material placed between them Both resonator mirrors are coated to reflect the laser wavelength thus containing it within the cavity while transmitting all others thus removing them from the cavity As the reflected light passes through the gain material stimulated emission produces two photons The two photons are trapped in the resonator and are reflected through the gain to become four four become eight and the numbers continue to increase geometrically until an equilibrium is reached where the excitation rate and emission rate of the gain medium are equal The light in the resonator forms standing waves with frequencies that depend on the resonator design Standing wave frequencies that are ampli fied in the gain material form the circulating light in the cavity This is the energy that is transmitted through the output coupler as the laser beam There is one standing wave pattern or cavity mode that has the simplest possible form termed TEM TEM go operation results from choosing the mirror curvatures and the shape and pumping geometry of the laser mate rial so that gain is confined along the central axis of the material This is further discussed in the section Diode Pumped Laser Design below The TEM mode appears brightest in the center and attenuates smoothly toward the edges of
65. mage to equipment Action may cause electrostatic discharge and cause damage to equip ment Condition or action may cause poor performance or error Text describes exceptional circumstances or makes a special refer ence Do not touch Appropriate laser safety eyewear should be worn during this opera tion Refer to the manual before operating or using this device xi Standard Units The following units abbreviations and prefixes are used in this Spectra Physics manual Quantity Unit Abbreviation mass kilogram kg length meter time second S frequency hertz Hz force newton N energy joule J power watt W electric current ampere A electric charge coulomb C electric potential volt V resistance ohm Q inductance henry H magnetic flux weber Wb magnetic flux density tesla T luminous intensity candela cd temperature Celsius C pressure pascal Pa capacitance farad F angle radian rad Prefixes tera 107 T deci 10 d nano 109 n giga 10 G centi 107 c pico 107 p mega 10 M milli 103 m femto 105 f kilo 10 k micro 109 U atto 10 a xiii Unpacking and Inspection Unpacking Your Laser Your Excelsior laser was packed with great care and its container was inspected prior to shipment it left Spectra Physics in good condition Upon receiving your system immediately inspect the outside of the ship ping container If there is any major damage holes in the container crush
66. maximum An On signal from the EMISSION keyswitch or from a TTL low signal applied to Pin 2 will only be accepted when ENABLE is active low Using the External Stable Signal Pin 1 When laser head temperature has reached normal operating range and the laser has been turned on and output power has stabilized an internal tran sistor connected to Pin 1 turns on thus pulling Pin 1 low This signals the laser is ready to use following a 3 to 5 second CDRH delay Pin 1 45V Stable or Emission Stable or I Indicator Emission Signal Gnd O O Gnd I I Power Supply l External Circuit Figure 6 3 Example Circuit for a Remote Stable Emission Signal Indicator A circuit similar to that shown in Figure 6 3 can be used to signal a remote controller that the laser is stable and emission has occurred or it can be used to turn a remote Enable or Emission indicator on and off The Pin 3 transistor can sink up to 20 mA maximum 6 3 Excelsior Diode Pumped CW Lasers Using the Service Alarm Signal Pin 10 Note sj The SERVICE alarm is activated on Pin 10 the pin is pulled low when the diode laser drive current reaches 95 of the factory set maximum limit Figure 6 4 shows an example of a circuit that can be used for monitoring the SERVICE alarm remotely The Pin 10 transistor can sink up to 20 mA maximum To allow the laser head to become fully stabile the Pin 10 signal
67. nd through a transistor when the laser reaches stable operation i e when laser output power is at the specified level and sta ble and laser head temperature is within the proper oper ating range The shutter can be opened at this time Refer to Using the External Stable Signal Pin 1 on page 6 3 2 Input Laser ON OFF When this pin is shorted to ground the laser will turn on fol lowing a 3 to 5 second delay Refer to Turning the Laser On and Off Pin 2 on page 6 2 for instructions 3 Output Laser ENABLE This pin becomes internally shorted to ground through a transistor when laser head temperature is within the proper operating range The laser may be turned on at this time Refer to Using the External Enable Signal Pin 3 on page 6 3 for instructions 4 Output Current Monitor This pin provides an output signal proportional to the current of the diode pump laser The scale is 100 mV Amp and maximum signal is 160 mV corresponding to 1 6 A 5 Output Laser Power Monitor This pin provides an output signal that is approximately pro portional to the power output of the laser Actual signal level depends on the laser model When nominal power 10096 is emitted from the laser the voltage on Pin 5 is about 100 mV typically 96 to 98 mV Example a Pin 5 signal of 50 mV for the Excelsior 532 150 indicates that laser power is about 75 mW 6 Ground Ground Input External Power Control This pin is used to vary the output
68. nes Service Centers Troubleshooting and Service Belgium Telephone 0800 11 257 Fax 0800 11 302 China Newport Corporation Beijing Representative Office Room 2305 Building B Tri Tower No 66 Zhongguancun East Road Beijing 100080 P R China Telephone 86 10 6254 7746 Fax 86 10 6255 6373 France MICRO CONTROLE Spectra Physics S A 1 rue Jules Guesde B t B ZI Bois de l Epine BP189 9106 Evry CEDEX France Telephone 33 1 60 91 68 68 Fax 33 1 60 91 68 69 Internet france Onewport fr com Germany and Export Countries Newport Spectra Physics GmbH Guerickeweg 7 D 64291 Darmstadt Germany Telephone 49 0 06151 708 0 Fax 49 0 06151 708 217 Internet verkauf newport de com Japan East Spectra Physics K K 4 6 1 Nakameguro Meguro ku Tokyo 153 0061 Japan Telephone 81 3 3794 5511 Fax 81 3 3794 5510 Internet spectra physics O splasers co jp Japan West Spectra Physics K K Nishi honmachi Solar Building 3 1 43 Nishi honmachi Nishi ku Osaka 550 0005 Japan Telephone 81 6 4390 6770 Fax 81 6 4390 2760 Internet spectra physics O splasers co jp And all European and Middle Eastern countries not included on this list 7 7 Excelsior Diode Pumped CW Lasers Netherlands Newport Spectra Physics B V Vechtensteinlaan 12 16 3555 XS Utrecht Netherlands Telephone 0900 555 5678 Fax 0900 555 5679 Internet netherlands Onewport de com Taiwan Newport
69. optical elements does not bilizing the laser reflect back through the window of the laser head Symptom Output power is unstable Possible Causes Corrective Action Loose cable connector Verify that all cables are securely connected Improper settings for the Verify that the controller PWR CONTROL switch is set to INT PWR CONTROL switch If laser power is controlled externally set the PWR CONTROL switch to EXT and provide a stable low noise 5 V signal to Pin 8 of the CONT con nector Laser is not warmed up Allow the laser to warm up for at least 5 minutes Laser head temperature is Measure the temperature of the baseplate If it is below 10 C or exceeds outside operating range 50 C or 45 C for Group B models verify the ambient temperature is within the allowable operating range and correct if necessary Refer to Table 5 1 Figure 5 1 and Figure 5 2 Verify the laser head baseplate is properly heat sinked Reflected laser light is desta Ensure that light reflected from any external optical elements does not bilizing the laser reflect back through the window of the laser head Troubleshooting and Service Replacement Parts The following is a list of parts that may be purchased to replace broken worn out or misplaced components Table 7 1 Replacement Parts Description Part Number Excelsior 10 mW 473 nm single mode Excelsior 50 mW 473 nm single mode Excelsior 20 mW 505 nm multi mode Ex
70. power of the lasers listed in Table 6 1 Refer to Changing Laser Output Power Pin 8 on page 6 4 for instructions 9 Output 12 Vdc This pin provides 12 Vdc 20 mA max This output can be used for external power control or for driving an external LED for indicating status 10 Output SERVICE Alarm Indicates the diode pump laser in the laser head is nearing its end of life To employ this open collector alarm refer to Using the Service Alarm Signal Pin 10 on page 6 4 11 Ground 12 Ground 13 N A or Reserved or Must be open on an Excelsior PS CDRH or it provides a Output Thermistor Alarm thermistor alarm on a Excelsior PS XC CDRH For the lat ter it indicates that the thermistor circuit inside the laser head has opened To employ this open collector alarm refer to Using the Thermistor Alarm Pin 13 on page 6 6 14 N A Reserved Must be open 15 N A Reserved Must be open 5 5 Excelsior Diode Pumped CW Lasers Chapter 6 Operation Danger Laser Radiation The Spectra Physics Excelsior lasers are Class IIIb and Class 4 High Power Lasers whose beams are by definition safety hazards Take pre cautions to prevent accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye damage Because the infrared IR beam of the 1064 nm lasers is invisible it is especially dangerous Infrared radiation passes easily through the cor nea of the eye
71. replacing or giving credit for the purchase price of any equipment that proves defective during the warranty period provided prior authorization for such return has been given by an authorized representative of Spectra Physics Spectra Physics will provide at its expense all parts and labor and one way return shipping of the defective part or instrument if required In warranty repaired or replaced equipment is warranted only for the remaining portion of the orig inal warranty period applicable to the repaired or replaced equipment This warranty also does not apply to equipment or components that upon inspection by Spectra Physics is found to be defective or unworkable due to abuse mishandling misuse alteration negligence improper installa tion unauthorized modification damage in transit or other causes beyond the control of Spectra Physics This warranty is in lieu of all other warranties expressed or implied and does not cover incidental or consequential loss Returning the Instrument for Repair 7 6 Contact your nearest Spectra Physics field sales office service center or local distributor for shipping instructions You are responsible for one way shipment of the defective part to Spectra Physics Instruments can be returned only in Spectra Physics containers We encourage you to use the original packing boxes to secure instruments during shipment If shipping boxes have been lost or destroyed we recommend ordering new o
72. roblem Suggested Solution s
73. ser resonator is machined from a solid piece of brass for exceptional thermal and mechanical stability The waste heat produced by the diode pump laser typically less than 2 W is removed from the laser head by thermal conduction through the baseplate The laser crystal is set to a stable operating temperature of about 45 C by a thermo electric cooler TEC located in the head beneath the laser cavity The mechanical design of the miniature laser head allows for mounting it using precision alignment pins Together with the excellent stability and boresight specifications of the Excelsior this facilitates both the design of the optical train of the application as well as the replacement of the laser head when the diode pump laser eventually reaches its end of life condi tion The Excelsior Power Supply Controller Power for the laser as well as monitoring and control capability is pro vided by one of two small separate power supply control units A standard 15 pin D sub connector is used for the LASER connector on the Excelsior PS XC CDRH model while a 26 pin SDR connector is used on the Excel sior PS CDRH model The Excelsior power supply provides output signals proportional to laser output power and diode laser pump current as well as an alarm for the diode lifetime and a status signal that can be used to control an external laser emission indicator These features are all available through the CON Trol interface on the back of the Ex
74. t value and becomes stable and it remains on as long as laser power is stable The laser typically reaches its set operating power and becomes stable about 10 seconds DPSS CDRH or 30 seconds DPSS XC CDRH after turning on the EMISSION keyswitch or after an On command has been received at Pin 2 of the CONTrol interface connector This indicator turns on when the EMISSION keyswitch is turned on see the prerequisites for turning on the keyswitch above and emission occurs 3 to 5 seconds later Note this indicator does not blink during the delay as it does on some other laser systems If the REMOTE interlock circuit is opened see the description below laser emission stops immediately and this indicator turns off If the REMOTE interlock switch is then closed again one of the following actions occur e Ona standard Class 3b laser or extended cavity XC laser if the key switch is still in the ON position the EMISSION indicator turns on again immediately and the laser turns on again following a safety delay of 3 to 5 seconds e Ona standard Class 4 laser if the keyswitch is still in the ON position the keyswitch must first be turned off then back on again in order to resume operation After it is turned back on the EMISSION indicator turns on again and the laser will turn on again after a safety delay of 3 to 5 seconds Pin 1 of the CONTrol connector can be used to control an external emission indicator See Chapter 6 for an examp
75. tals A variety of means exist to eliminate all but one longitudinal mode in such a case including the insertion of an etalon into the resonant cavity An eta lon is type of resonator and in its simplest form is just a thin flat piece of glass resembling a microscope slide Placed intracavity the mode separa tion of this thin element will limit the modes allowed to resonate Nd as a Laser Medium 3 4 The output of one laser can be used to excite or pump the gain medium of another laser e g a diode laser can be used to pump a solid state laser The Excelsior lasers use a diode laser to pump Nd ions added to either a crystal of yttrium vanadate Nd YVO or yttrium aluminum garnet Nd YAG The properties of neodymium doped crystals are the most widely studied and best understood of all solid state laser media The four level Nd YAG ion scheme is shown in Figure 3 3 The active medium is ionized neody mium which has principle absorption bands in the red and near infrared 20 r Pump EF Bands 18 r 16 F 4F 3 0 11502 cm 1 Ro LE A ME TARO 11414 Ry u l d Laser Pap Transition 10 L Laser Aue I Transition WT 6000 cm1 8 Pa UU Fa 2 4000 cm 1 6 As af 2526 5 o cuu apap 2473 4 F ila we d W 242146 e REF 2111 ue lt gt 2029 2 She qe SCC DEEN Ground Level 134 NG Figure 3 3 Energy Level Scheme for the Nd Ion in YAG System Description The electrons in the
76. tation of the beams within the crystal are carefully controlled This technique is referred to as critical phase matching LBO and KTP are nonlinear crys tals that lend themselves well to this technique The high nonlinear coefficient of KTP has made it historically a very popu lar material for conversion of lower power 1064 nm infrared lasers to green wavelengths KTP can be fabricated in a specialized structure that keeps the infrared and green beams in an approximate phase matched condition over a longer distance than in a typical bulk crystal Although LBO has a comparatively smaller nonlinear coefficient it pro duces no spatial walk off of the fundamental and second harmonic beams This favors a long interaction length for higher gain Consequently LBO has subtle advantages that provide superior conversion efficiency of CW infrared laser light to blue wavelengths The second harmonic power P produced by frequency doubling is given by e deaPal 9 Poo A 4 where d is the effective nonlinear coefficient P is the fundamental input power I is the effective crystal length d is a phase matching factor and A is the cross sectional area of the beam in the crystal The important point to note from equation 4 is that the second harmonic output is dependent upon the square of the fundamental peak power High conversion efficiencies can therefore be achieved by placing the doubling crystal within the laser resonator
77. ternal Enable Signal Pin 3 on page 6 3 When the laser is stable the STABLE signal Pin 1 is pulled low see Using the External Stable Sig nal Pin 1 on page 6 3 Internal I 5 V I Laser l On Off Pin 2 I l Input I Gnd Gnd Power Supply d External Circuit Figure 6 1 Example of a typical laser On Off control circuit Use a switching circuit similar to that shown in Figure 6 1 to turn the laser on and off When the external transistor connected to Pin 2 is turned on thus pulling Pin 2 low the diode pump laser turns on and emission occurs After the laser has received this On command it is ready to perform to specifications after 3 to 5 seconds Note the external transistor in the figure above can be replaced by a simple mechanical switch or relay Operation Using the External Enable Signal Pin 3 Note When laser head temperature is within normal operating range i e when the resonator has stabilized an internal transistor connected to Pin 3 turns on thus pulling Pin 3 low 5 V Enable l Indicator Enable Signal Gnd 9 Gm I Power Supply I External Circuit Figure 6 2 Example Circuit for a Remote Enable Signal Indicator A circuit similar to that shown in Figure 6 2 can be used to signal a remote controller that the laser is ready to be turned on or it can be used to turn a remote Enable indicator on and off as shown in the example The Pin 3 transistor can sink up to 20 mA
78. to operate A jumper is supplied to short the pins if an optional safety switch is not employed The jumper can be modified jumper removed for use as a connector for a safety switch Figure 5 3 REMOTE Connector Jumper Plug 3 Connect the power supply ac power cable to your utility power source The external control interface through the CONTrol connector on the back of the power supply allows the laser to be turned on and off from a remote signal source connected to Pin 2 If a remote control signal is 5 3 Excelsior Diode Pumped CW Lasers to be used the EMISSION CONT switch on the side of the power supply must be set to EXT If it is not to be used this switch must be set to INT The external control interface also allows the output power of some laser models to be controlled externally using a remote signal source at Pin 8 A list of compatible laser heads is provided in Table 5 2 If laser power is to be controlled externally the PWR CONT switch on the side of the power supply must be set to EXT Otherwise this switch should be left in the INT position for continuous maximum power out put If external control of the laser is desired proceed to connect the CONTrol connector on the power supply Table 5 2 Lasers capable of variable output power Excelsior 473 10 Excelsior 473 50 Excelsior 505 20 Excelsior 515 50 Excelsior 532M 20 Excelsior 532 50 Excelsior 532 100 Excelsior 532 150 Excelsior 532 200
79. uce a continuous laser beam from an exceptionally compact package These small rugged diode pumped solid state lasers are especially well suited for applications requiring a low noise high quality continuous wave CW beam All Excelsior lasers are designed to operate at constant output power However several models allow the operator to vary laser power from 50 to 100 via an external interface Table 1 1 on page 1 2 lists the different models These lasers deliver efficient stable light with the excellent spatial mode that is critical for applications in graphics photo finishing and flow cytom etry Individual Excelsior models operate in either single or multiple longi tudinal mode Again refer to Table 1 1 The Excelsior laser heads are designed for precision mounting and align ment of the beam which together with the specified boresight of the out put simplifies the task of designing the master optical train or replacing a laser head in the master system All optical components including the diode pump source are contained in the laser head itself The lasers are powered and controlled by a small separate power supply controller unit The power supply interface allows the laser to be monitored and operated using analog signals applied to the connector on the back of the power supply All Excelsior models use a similar power supply to deliver electrical power to the laser head through the cable provided with the system
80. ue ege 4 1 Connections ire maana GP rette lA a e 4 2 Excelsior Power Supply Controller liliis rn 4 2 Front Range agapan anG Seed ak E PNE Present Ee eue Ver d EFE 4 2 Back Patel evite ropes Wa aede v Ru Oh AAA BM S 4 4 Controls on the Power Supply Side Panel eres 4 6 Chapter 5 Installation u eR EE ERE 5 1 POWER un A AE e ere 5 1 Thermal Management 5 1 Installing the Hardware Rh eee 5 3 Mounting the Laser Head 5 3 Mounting the Power Supply 000 hrs 5 3 Connecting the Cables hr 5 3 External Control Connector 0c hrs 5 4 Chapter TL d DEE 6 1 Operating the Laser from the Power Supply 2 e 6 1 Turning the Laser On and Off hn 6 1 Operating the Laser Using the External Control Interface seen 6 2 Turning the Laser On and Off Pin 2 1 2 20 0c ren 6 2 Using the External Enable Signal Pin 31 6 3 Using the External Stable Signal Pin 6 3 Using the Service Alarm Signal Pin 10 6 4 Changing Laser Output Power Ping 6 4 Monitoring Laser Output Power Pin pi 6 6 Using the 12 Vdc Output Ping 6 6 Using the Thermistor Alarm Pin 13 2 eee 6 6 Interlock Jumper lg m Hae NANA PEA E ae A ENG Me t E E RS 6 7 Chapter 7 Troubleshooting and Service 000 cece eee eee eee eee 7 1 Maintenance CDM cc 7 1 Service Training Programs nennen een een 7 2 Troubleshooting ui lcd PR n ERR ERR dedere PEE gy ERR ENN NEEN 7 2 R
81. ut signal for exter nal power control Symptom Low power Possible Causes Corrective Action Incorrect power measurement Ensure that output power is measured as it leaves the laser head before the output beam enters any external optical elements Shutter is clipping the beam Verify the hand operated shutter is fully open Loose cable connector Verify that all cables are securely connected Laser is not warmed up Allow the laser to warm up for at least 5 minutes Dirty output window Clean the laser head output window Laser head temperature out Measure the temperature of the baseplate If it is below 10 C or exceeds side operating range 50 C or 45 C for Group B models verify the ambient temperature is within the allowable operating range and correct if necessary Refer to Table 5 1 Figure 5 1 and Figure 5 2 Verify the laser head baseplate is properly heat sinked Symptom Low power Troubleshooting and Service Reflected laser light is desta bilizing the laser Diode pump laser has reached its end of life Improper settings for internal power control External control Incorrect settings for external power control Incorrect use of external power control Ensure that light reflected from any external optical elements does not reflect back through the window of the laser head Contact your Spectra Physics service representative about replacing the laser head For internal power control the PW

Excelsior Scientific.book - Spectra

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