IJET vol 1 no 1
Contents
1. Ai N Splitter Polarizing beamsplitter Pump laser Second Detector Third Detector _ Connegor Block Data acquisition card in the PC af a eH p E p 1 Cable NI PCI 6602 Figure 4 The setup of the Data Acquisition DAQ for photons detection in the light 30 International Journal of Engineering and Technology Vol 1 No 1 April 2009 1793 8236 Counter Setting Coincidence Setting Data Collection g Calculation Figure 5 Flowchart for probability calculation TABLE 1 SHORT LIST OF SOME COMMON TRANSDUCERS AND THE PHENOMENA THEY CAN MEASURE Temperature Thermocouples Resistive temperature device RTDs Themistors Light Vacuum Photo sensors Sound Microphone Force and pressure Strain gauge Piezoelectric transducers Position and displacement Potentiometers Linear voltage differential transformer Optical encoder Fluid Head meters Rotational flowmeters pH pH electrodes TABLE 2 ELECTRICAL CONNECTION FOR THE COUNTERS Detector 1 0 39 Detector 2 1 35 Coincidence 3 2 31 Ground 36 International Association of Computer Science and Information Technology WWW IACSIT ORG International Journal of Engineering and Technology Vol 1 No 1 April 2009 1793 8236 PHOTONS EXISTENCE COUNTING Counter Number COUNTER 1 COUNTER 2 COUNTER 3 z K H k E Initial count initial count 1 ini2. mechanics the wave function of the photon has to collapse onto either one of the two detectors The probability of obtaining two or more photons at the same time is negligible Figure 1 shows the difference between a triggered classical photon stream and the triggered single photon stream ideal An ideal single photon source emits one photon with certainty or in a specified time interval 4 In this paper the automation system for single photon generation and detection is based on color center in diamond Color center is also called nitrogen vacancy The reason for choosing this approaches are e Suitable for room temperature e Much simpler setup than any other quantum emitter approach As for the automation of the detection it will enable computer to counts the coincidence and raw data counts from the single photon detector Besides that second order correlation values can be calculated as described later II DATA ACQUISITION SYSTEM Data acquisition system involves gathering signals from measurement sources and digitizing the signal for storage analysis and presentation on computer Three main components to be considered in the systems are 5 1 Signals The signals are standard logic pulses coming from the detectors 2 DAQ hardware DAQ hardware acts as the interface between the computer and the outside world 3 Driver and software Connector block CB 68LP National Instrument as shown in Figure 2 is a necessary nee
3. probabilities can be expressed in term of measured counts rates The probability of detection at B in a short time interval Af is simply given by the average rate of detections multiplied by Af The average rate of detections at B is just the number of detections N divided by the counting time T that we are averaging over The probabilities for B detection and BB coincidences are given similarly r T p t T B Ave Js T Substituting this into equation 2 we get EAr 4 N N At Where B B and BB are counter 1 counter 2 and counter 3 respectively The flowchart and SubVI block for g2 calculation are shown in Figure 5 When this program starts first thing to be done is to set the counter setting Three independent counters are needed in this program For each counter the input output has to be set according to the conn A labVIEW program is developed which will be used to count the number of photons in the light when we specified the counter that we are using and the device number The counter number should be specified according to the pin connector assignments that can be found in the manual of data acquisition card that is been used Input must be connected to the correct pin and should specify the correct counter number in LabVIEW to get the output Connection can checked using measurement and automation software Figure 6 shows the virtual instrument VI that has been created to count photons in the
4. International Journal of Engineering and Technology Vol 1 No 1 April 2009 1793 8236 A LabVIEW Based Counting Photons Existence in the Light Hazem I Ali Ahmed M Hassan and Ali Faroug Lutfi Abstract Lab VIEW developed by National Instruments is a graphical programming environment suited for high level or system level design It allows integrating different signal processing components or subsystems within a graphical framework This paper introduces a LabVIEW based counting number of photons in the light The probability of the photon existence is calculated in a separated SubVI using LabVIEW In this paper the data acquisition card NI PCI 6602 is used for this purpose Index Terms Lab View Photons existence Data acquisition I INTRODUCTION In 1905 Albert Einstein published the theory of photoelectric effect which gave the idea of photons to describe the origin of light This theory extended from classical radiation to quantized radiation leading to a clearly point of view of the statistics of light The understanding of the interaction between light and matter following from these developments formed the basis of quantum optics After the introduction of the correlation experiment in 1956 and also the forming of quantum formulation of optical coherence by R J Glauber this field started to flourish Many experiments based on entangle photon pairs and quantum emitter such as using trap ions quantum dots molecules a
5. ded for connection to DAQ card in computer It uses a 68 I O shielded cable SH6868 National Instrument for data transferring process It is possible to use the versatile National Instruments counter timer DAQ card NI PCI 6602E device shown in Figure 3 to create a wide variety of measurement solutions including measuring a number of time related quantities counting events or totalizing and monitoring position with quadrature encoders You can also use counter timers to generate pulses and pulse trains Counter timers often fulfill critical timing functions as components of complex measurement systems 6 The NI 660x counter timers use the NI TIO a National International Association of Computer Science and Information Technology WWW IACSIT ORG International Journal of Engineering and Technology Vol 1 No 1 April 2009 1793 8236 Instruments ASIC chip specifically designed to meet the counting and timing requirements of measurement applications that are beyond the capabilities of off the shelf components The wider functionality and simple programming interface make the NI 660x your best choice for counting and timing applications Example applications include frequency measurement position measurement generation of retriggerable pulses frequency shiftkeying two signal edge separation measurements continuous buffered event counting and continuous buffered pulse train measurements The NI 660x counter timer devices are readil
6. e light The facilities of the NI PCI 6602 data acquisition card Timer Counter are used for counting the number of photons REFERENCES 1 Holbrow C H E J Galvez and M E Parks 2002 Photon quantum mechanics and beam splitters Am J Phys 70 260 265 2 N Kehtarnavaz N Kim and I Panahi Digital signal processing system design using LabVIEW and TMS320C6000 IEEE Digital Signal Processing Workshop 2004 3 Chance Elliott Vipin Vijayakumar Wesley Zink and Richard Hansen National Instrument LabVIEW A programming environment for laboratory automation and measurement The association for Laboratory Automation 2007 4 A P French and Edwin F Taylor Introduction to Quantum Physics Chapman and Hall London 1974 pp 231 278 5 D F Styer The strange world of quantum mechanics cambridge U P New York 2000 6 National Instruments DAQ 6023E 6024E 6025E user manual January 1999 Edition 7 www instrumentation central com 8 National Instruments DAQ 6023E 6024E 6025E user manual January 1999 Edition 9 www ni com Tiggered classical photon stream Tiggered single photon stream ideal a f jou NATIONAL Figure 2 CB 68LP and also shielded cable International Association of Computer Science and Information Technology WWW IACSIT ORG International Journal of Engineering and Technology Vol 1 No 1 April 2009 1793 8236 Figure 3 Counter timer Data Acquisition Card
7. hown in table 2 IV PHOTON EXISTENCE PROBABILITY CALCULATION Second order correlation function is known as the intensity correlation function or the second order coherence function It is defined by 9 I t t a Daa t our 7 pos oy HOON 1 where I are the intensities The probability function 2 can be used to describe the photon correlation and the quantum properties of light Theoretically one could use a fast photon counter with zero dead time or the ability to count multiple photons to measure g directly In actual experiment a hardware setup is needed to show the correlation between two fluctuating currents by recording and analyzing the product of the currents The Connection on the connector block and also the number of the device Other parameters need to be set are the initial counts count direction and type of edge beam splitting ratio and the losses in the two arms do not matter At very low intensities the photo detector becomes a photon counter For a photon counter the probability of 2 count is proportional to the intensity of light In this case g is expressed in terms of the photon number at the two counters as Pry g t P P P P3 is the detector B B in a time interval Af and Pos is the 2 where probability of a detection at probability of making detections at both B and B in the same time interval coincidence However the
8. light before we run the program we must set the counter number 3 The buffer of the computer records data collected from detector 1 detector 2 and also coincidence counter 3 from the source These data will be sent to g2 function SubVI to 28 International Journal of Engineering and Technology Vol 1 No 1 April 2009 1793 8236 calculate the probability of the detected photons Finally the program will stop after counting all the points These data will be saved in a file Figure 7 shows the block diagram of the main program using LabVIEW V SOFTWARE DESIGN A labVIEW program is built to be used for counting a number of photons in the light when the counters and device number are initialized The counter number should be specified according to the pin connector assignments which can be found in the manual of data acquisition card that is used Input must be connected to the correct pin and should specify the correct counter number in LabVIEW to get the output Connection can be checked using measurement and automation software Figure 6 shows the front panel of the Virtual Instrument VI program that counts photons existence in the light While table 3 shows the probability of the photons existence depending on the number of photons detected in the light for fixed time interval and counting period equal to 5000 s VI CONCLUSION The LabVIEW based DAQ system is used to prove the existence of the photons in th
9. nd colour centre have been studied intensively to realize their potential as a single photon source 1 LabVIEW Laboratory Virtual Instrumentation Engineering Workbench is a graphical programming environment developed by National Instrument NI which is well suited for high level or system level design This programming approach is based on building blocks called Virtual Instruments VIs 2 3 In this paper a LabVIEW program is used for counting the photons in the light through DAQ card model NI PCI 6602E of National Instruments The objective of this paper is setting up the detection apparatus and automates the data acquisition system for single photon detection Automation for the detection requires a programme that can count for the coincidence and raw counts of the counter Besides it can also calculate second order correlation values for the collected data Il SINGLE PHOTON SOURCE Single photon source is a source that can produce photon with antibunching characteristic In general antibunching Control and Systems Engineering Department University of Technology Baghdad Iraq 227 characteristic is a quantum state of light where the photon statistic deviates strongly from the classical distribution 3 For example if one photon state was sending to a beam splitter and photon counting detectors were placed at the transmitted and reflected beams position no coincidence will be observed From the principle of quantum
10. tial count 2 initial count 3 Count up a a a Count down z y J Externally controlled count direction 1 EEEE EnA E o Count Up a Count Up e edge 2 edge 3 aling s isi Risna Rising c i NUMBER OF COUNTS ontro Counter Max value z G2 VALUE Counter Count 1 Photons Count 1 setting Jo a Count E values Elapsed Time G2 Counter Count 2 Photons Count 2 from jo fo jo counters Counter Count 3 Photons Count 3 io 0 Figure 6 Front Panel of virtual instrument TABLE 3 PROBABILITY CALCULATION USING THREE COUNTERS WITH COUNTING TIME 5000 s 0 0234 500 500 700 0 014 1300 1300 2800 0 0082 3050 3050 6500 0 00349 32 International Journal of Engineering and Technology Vol 1 No 1 April 2009 Ege 0 324 ount direction 0 initial count 0 a counter 0 cy DAAM CI Cnt Edges Y 1793 8236 Read and count digital events OK message warnings Y counter Count 1 dge 1 bH status j 4 direction 1 Ep Max value rea total Count 1 initial count 1 od usm timeout ounter 1 TE rer CI Cnt Edges ount direction 2 4 initial count 2 K message warnings gt a ET DAC 7 aee c2 1 23 oHa Bid fa Count 3 foen y Si Elapsed Time j t ave counter Ini
11. tializin A count data and armed Total count sub VI G2 function counters calculation sub VI Clear and Error message Elapsed time Figure 7 Block diagram of the counting multiple digital events JAE IACSIT International Association of Computer Science and Information Technology WWW IACSIT ORG
12. y integrated into measurement systems that require synchronization across multiple hardware devices because they are equipped with the National Instruments PXI trigger bus or the RTSI bus 5 7 In addition to counter timer functionality the NI 660x _ products include TTL CMOS compatible digital I O ports that are bit configurable for input or output Data acquisition begins with the physical phenomenon to be measured This physical phenomenon could be the temperature of a room the intensity of a light source the pressure inside a chamber the force applied to an object or many other things An effective DAQ system can measure all phenomena A transducer is a device that converts a physical phenomenon into a measurable electrical signal such as voltage or current The ability of DAQ system to measure different phenomena depends on the transducer to convert the physical phenomena into signals measurable by the DAQ hardware Transducers are synonymous with sensors in DAQ systems 8 There are specific transducers for many different applications such as measuring temperature light pressure or fluid flow as illustrated in table 1 In order to get data from the running experiment correctly make input and output signal connections is very important A correct connection is shown in Figure 4 Before starting to do any connection pin code for PCI6602 and the connector block are required The electrical connections for the counters are as s
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