Recent advances in the detection efficiency calibration of Silicon Single-Photon Avalanche Diodes using double attenuator technique

Size: px

Start display at page:

Download "Recent advances in the detection efficiency calibration of Silicon Single-Photon Avalanche Diodes using double attenuator technique"

Julian Patterson
5 years ago
Views:

Recent advances in the detection efficiency calibration of Silicon Single-Photon Avalanche Diodes using double attenuator technique S. Kück 1, M. López 1, K. Dhoska 2, T. Kübarsepp 2,3, H. Hofer 1, B.

1 Recent advances in the detection efficiency calibration of Silicon Single-Photon Avalanche Diodes using double attenuator technique S. Kück 1, M. López 1, K. Dhoska 2, T. Kübarsepp 2,3, H. Hofer 1, B. Rodiek 1, G. Porrovecchio 4, M. Šmid 4 1 Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116, Braunschweig, Germany 2 Tallinn University of Technology, Ehitajate tee 5, Tallinn, Estonia 3 AS Metrosert, Teaduspargi 8, Tallinn, Estonia 4 Cesky Metrologicky Institut (CMI), V Botanice 4, Praha 5, Czech Republic

2 Motivation Silicon Single-Photon Avalanche Diodes (Si-SPADs) important for scientific research: experimental quantum optics quantum cryptography quantum computing medicine biology astrophysics Wherever low photon fluxes need to be measured! Seite 2

3 Motivation Si-SPADs are commercially available Detection efficiency important parameter for application (besides detection jitter, dead time, after-pulsing probability [1]) Traceability to a national standard is not realized in a standardized way! Customers have to measure themselves or rely on the values given by the manufacturer Pilot study for detection efficiency under way [2] [1] C. J. Chunnilall, I. P. Degiovanni, S. Kück, I. Müller, A. G. Sinclair; Metrology of singlephoton sources and detectors: a review Opt. Eng. 0001;53(8): doi: /1.oe (2014) [2] CCPR WG-SP TG11 Single Photon Radiometry Seite 3

4 Motivation Measurement of detection efficiency Two-photon correlation technique Laser NL-crystal producing photon pairs N C = A B N N A = A N Trigger detector N: number of photon pairs N C : number of coincidences A = N C / N B is the detection efficiency A is DUT channel, B is trigger channel No external standards required! DUT Device Under Test B N B = B N 1 N. T coincidenc es N triggers N N accidentalcoincidenc es false triggers Klyshko, D.N. Kvantovaya Elektron. 1977, 4, Klyshko, D.N. Kvantovaya Elektron. 1980, 7, Seite 4

5 Motivation Measurement of detection efficiency Attenuation technique Amplifier + DVM Read Out F = V S /s S Standard Source Beam shaping Optics SPAD Seite 5

6 Motivation Measurement of detection efficiency Attenuation technique Read Out Attenuation in the 10 6 range! Amplifier + DVM Standard Source Beam shaping Optics Attenuator SPAD Seite 6

7 Motivation Comparison Correlation technique Attenuation technique From: W. Schmunk, M. Rodenberger, S. Peters, H. Hofer, S. Kück, Radiometric Calibration of Single Photon Detectors by a Single Photon Source based on NV-centers in diamond, Journal of Modern Optics 58, 1252 (2011). References therein: [3] Burnham, D.C; Weinberg, D.L. Phys. Rev. Lett. 1970, 25, [6] Rarity, J.G.; Ridley, K.D.; Tapster, P.R. Appl. Opt. 1987, 26, [9] Migdall, A.L.; Datla, R.U.; Sergienko, A.; Shih, Y.H.Metrologia 1996, 32, [10] Brida, G.; Castelletto, S.; Degiovanni, I.P.; Novero, C.;Rastello, M.L. Metrologia 2000, 37, [13] Ghazi-Bellouati, A.; Razet, A.; Bastie, J.; Himbert,M.E.; Degiovanni, I.P.; Castelletto, S.; Rastello, M.L.Metrologia 2005, 42, [14] Polyakov, S.V.; Migdall, A.L. Opt. Express 2007, 15, [17] Beaumont, A.; Cheung, J.Y.; Chunnilall, C.J.; Ireland, J.; White, M.G. Nucl. Instrum. Methods Phys. Res., Sect. A 2009, 610, Seite 7

8 Motivation A tabletop, easy-to-handle measurement setup is presented based on the multiple attenuation principle Full traceability to the national primary standards Seite 8

9 Outline Introduction / Motivation Measurement principle Improvements Alignment procedure Filter transmission measurements Results Homogeneity measurements Comparison with Si-Diode Summary Seite 9

10 Measurement principle Calibration of a Si-SPAD via comparison with a calibrated standard Si-diode Comparison cannot be carried out directly, because of the low photon flux applied to the Si-SPAD detector: Si-SPAD: approx Photons/s (i.e. approx. 30 fw) This is taken care of by using appropriate neutral density filters, which are calibrated in-situ in the same setup. Transmission of such a filter has to be in the order of approx. 10 7! Such a high attenuation is practically not possible to be measured with a standard Si-diode: Implementation of multiple attenuator technique Seite 10

11 Measurement principle - Step 1 Microscope objective Filter 3 T = Filter 2 T = Variable Filter OD = Beam splitter Laser 770 nm Si-Diode Si-SPAD Monitor detector V A s Φ 1 1 Si,1 1 Seite 11

12 Measurement principle - Step 2 Microscope objective Filter 3 T = Filter 2 T = Variable Filter OD = Beam splitter Laser 770 nm Si-Diode Si-SPAD Monitor detector V A s Φ A s T Φ 2 2 Si,2 2 2 Si,2 F2 1 Seite 12

13 Measurement principle - Step 3 Microscope objective Filter 3 T = Filter 2 T = Variable Filter OD = Beam splitter Laser 770 nm Si-Diode Si-SPAD Monitor detector V A s Φ A s T Φ 3 3 Si,3 3 3 Si,3 F3 1 Seite 13

14 Measurement principle - Step 4 Si-Diode Microscope objective Filter 3 T = Filter 2 T = Variable Filter OD = Beam splitter Laser 770 nm Si-SPAD Monitor detector Φ T T Φ V CR η 4 η F2 F3 1 4 hc hc λ λ Seite 14

15 Measurement principle Si-Diode Microscope objective Filter 3 T = Filter 2 T = Variable Filter OD = Beam splitter Laser 770 nm Si-SPAD V V V V A 1 A A 2 3 CR s s s Si,1 Si,2 Si,3 Φ 1 Φ Φ 2 3 Φ4 η hc λ A A 3 2 s s T η Si,2 Si,3 F2 T T F2 F3 Φ Φ TF3 Φ hc λ η hc λ A2 A A 1 3 Monitor detector CR V V V s Si,2 s s Si,1 Si,3 Seite 15

16 Measurement principle Si-Diode Microscope objective Filter 3 T = Filter 2 T = Variable Filter OD = Beam splitter Laser 770 nm Si-SPAD Monitor detector hc A A V 1 V 2 3 Mon1 Mon ssiffilt ssiffilt A V 1 2 V3 A1 Q2Q3 V Mon2 CR V V Mon3 hc A A Q Q Seite 16

17 Measurement Measurement principle different principle photon fluxes Microscope objective Filter 3 T = Filter 2 T = Variable Filter OD = Beam splitter Laser 770 nm Si-Diode Si-SPAD hc A A V 1 V 2 3 Mon1 Mon ssiffilt ssiffilt A V 1 2 V3 A1 Q2Q3 V Mon2 CR V V Mon3 hc A A Monitor detector Q Q Seite 17

Measurand Unit Description Value Measurement uncertainty budget Standard uncertainty Distribution Sensitivity coefficient Contribution Contribution h Js Planck constant 6.626206957 10-34 Js 1.

0005070 10 6 V/A 20.8 V/A Rectangular 640 10-12 13 10-6 0.0 % A 2 V/A Amplification factor 1.0009520 10 9 V/A 53100 V/A Rectangular 640 10-12 34 10-6 0.0 % A 3 V/A Amplification factor 1.

18 Measurand Unit Description Value Measurement uncertainty budget Standard uncertainty Distribution Sensitivity coefficient Contribution Contribution h Js Planck constant Js Js Rectangular % c m/s Speed of light m/s m Wavelength m m Rectangular % A 1 V/A Amplification factor V/A 20.8 V/A Rectangular % A 2 V/A Amplification factor V/A V/A Rectangular % A 3 V/A Amplification factor V/A V/A Rectangular % Q 1 1 Ratio V 1 /V Mon Standard % Q 2 1 Ratio V 2 /V Mon Standard % Q 3 1 Ratio V 3 /V Mon Standard % Q 4 1/V/s Ratio CR/V MonSPAD /V/s /V/s Standard % s Si A/W F F 1 Spectral responsivity of Si-Diode Factor for the use of two filters 1 Detection efficiency Standard A/W A/W Standard % Rectangular % SPAD = (k = 2) SPAD = % (k = 2) Seite 18

19 Measurement uncertainty budget main components s Si A/W Spectral responsivity of Si-Diode A/W A/W Standard % F F 1 Factor for the use of two filters Rectangular % Spectral responsivity of Si-diode: Caused by linearity measurements and its uncertainty Filter transmission: Total filter transmission equals multiplication of two single filter transmissions? Seite 19

20 Measurement uncertainty budget main components Filter transmission: total filter transmission equals multiplication of two single filter transmissions? Validation with measurements of filters with higher transmission! Thus, it is possible to determine the filter transmission of each individual filter, but also the overall transmission of the filter combination! Filter 2 (NG11, OD 0.3): T F2 = Filter 3 (NG4, OD 0.6): T F3 = Individual measurements: T single = T F2 T F3 = Combined measurement: T combined = Deviation: 0.3 % Correction factor F F = T combined /T single = (Standard uncertainty is estimated as difference T single T combined = ) Seite 20

21 Measurement setup Improvements Standard detector: Integrating sphere with Si-diode instead of Si-diode only Automated alignment procedure Si-Diode Integrating Sphere Microscope objective Beam splitter Variable Filter Laser 770 nm Si-SPAD Filter 3 Filter 2 Monitor detector Seite 21

22 Measurement setup Improvements Standard detector: Integrating sphere with Si-diode instead of Si-diode only Automated alignment procedure Seite 22

23 Improvement of measurement setup Standard detector Integrating sphere with attached detector: Diameter: 4.0 inch Coated with Spectralon Si-photodiode attached to one port Absolute responsivity of the sphere is calibrated against a trap detector, traceable to PTBs cryogenic radiometer Seite 23

Rel. Deviation Improved filter transmission measurements λ (nm) Filter 2 Filter 3 Combined Filters Deviation (%) 766 0.0186882 0.0086968 0.0001626 0.020 768 0.0188345 0.0087792 0.

0194161 0.0091136 0.0001769-0.012 780 0.0195284 0.0091665 0.0001791 0.035 781 0.0195746 0.0091978 0.0001800-0.011 Smaller deviation due to inhibited back reflexion into the setup!

24 Rel. Deviation Improved filter transmission measurements λ (nm) Filter 2 Filter 3 Combined Filters Deviation (%) Smaller deviation due to inhibited back reflexion into the setup! 0,06% Deviation between single and combined filter transmissions for wavelengths between 766 nm and 781 nm 0,04% 0,02% 0,00% -0,02% -0,04% -0,06% Wavelength (nm) Seite 24

25 Improvement of measurement setup Si-SPAD alignment Alignment of the Si-SPAD-detector is of highest importance: absolute position, reproducibility to re-align Calibration result only valid for the same conditions, especially for the same irradiation conditions: Position on the detector Diameter of irradiating beam Alignment of the Si-SPAD detector carried out using motorized XYZ-translation stages in an automatic manner. Optimal alignment position of the Si-SPAD is the focal plane of the objective, since at this position the laser beam is completely within the active area of the Si-SPAD. Seite 25

front of and behind the objective focal plane (nearly)

26 Procedure: Improvement of measurement setup Si-SPAD alignment 1. Two beam profile measurements (xy-scan using Si-SPAD) in front of and behind the objective focal plane (nearly) Gaussian beam profiles! Beam much larger than detector area Seite 26

27 Improvement of Si-SPAD measurement alignment setup procedure Si-SPAD alignment Procedure: 2. Calculation of focal plane f of the microscope objective using the geometric parameters of the two measured beam profiles: f d 1 Z d 2 1 d d 2 2 Z 1 Z 1, Z 2 : scan positions in the z-axis d 1, d 2 : beam diameters Seite 27

algorithm [1]: x center N x i i1 N i1 s s i i y center N y i i1 N i1 s s i i s i : detector signals x i, y i : scanning positions in x- and

28 Improvement of Si-SPAD measurement alignment setup procedure Si-SPAD alignment Procedure: 3. xy-scan at calculated focus position Rectangular shape, active area >> laser beam profile Centre of the rectangular profile calculated using centroid algorithm [1]: x center N x i i1 N i1 s s i i y center N y i i1 N i1 s s i i s i : detector signals x i, y i : scanning positions in x- and y-coordinates [1] D. R. Neal, R. J. Copland, D. A. Neal, D. M. Topa, and P. Riera, Measurement of lens focal length using multi -curvature analysis of Shack-Hartmann wavefront data, Proc. SPIE 5523, (2004). Seite 28

29 Improvement of measurement setup Si-SPAD alignment Results: Scan number z-position (mm) x-center (mm) y-center (mm) Error (%) Diameter (mm) Seite 29

Detection efficiency Results and Uncertainty hc A A 2 A 1 3 Q Q 1 Q Q 2 4 3 s Si F filt Uncertainty component Uncertainty (%) Planck constant, h 2.52 x 10-7 Speed of light, c 0.

004 Ratio V 2 /V Mon2, Q 2 0.015 Ratio V 3 /V Mon3, Q 3 0.05 Ratio CR/V MonSPAD, Q 4 0.036 Spectral responsivity, s Si 0.15 Factor for the use of two filters, F filt 0.

30 Detection efficiency Results and Uncertainty hc A A 2 A 1 3 Q Q 1 Q Q s Si F filt Uncertainty component Uncertainty (%) Planck constant, h 2.52 x 10-7 Speed of light, c 0.0 Wavelength, λ Amplification factor, A Amplification factor, A x 10-6 Amplification factor, A x 10-6 Ratio V 1 /V Mon1, Q Ratio V 2 /V Mon2, Q Ratio V 3 /V Mon3, Q Ratio CR/V MonSPAD, Q Spectral responsivity, s Si 0.15 Factor for the use of two filters, F filt Combined uncertainty, u c Main contribution: Standard detector u(η SPAD ) 0.16 % (770 nm, cps) However, this is the ideal value, in day-to-day calibrations, approx. 1 % seems reasonable! Seite 30

31 Procedure: Investigation of the detection efficiency homogeneity Scanning the Si-SPAD active area with a focused laser beam: 10 µm (beam << active area) Monitor detector to account for laser power fluctuations. Relative measurement normalized to responsivity in center: N N xi, y j x, yrel N center s mon s center moni, j N xi, yj : Si-SPAD counts for the (x,y)-position N center : Si-SPAD count rate at center position N x=0, y=0 s mon : signal of monitor detector The homogeneity of the detection efficiency may be defined as the relative standard deviation of the relative detection efficiency for a defined region. Seite 31

the Si-SPAD detectors Laser beam diameter B approx.

Relative values are within ± 1 % for the main active

32 Investigation of the detection efficiency homogeneity - Results Relative spatial detection efficiency of the Si-SPAD detectors Laser beam diameter B approx. 10 µm. Relative values are within ± 1 % for the main active region of the detectors, at the border of the active regions the values drop. Region 1: 0.85 % ( = 120 µm) Region 2: 0.3 % ( = 40 µm) Homegeneities Region 1: 2.2 % ( = 40 µm) Region 2: 0.13 % ( = 20 µm) Seite 32

33 Comparison: DE (Si-SPAD) calibrated directly against Si-Diode (CMI) and PTB-standard setup CMI low optical flux standard PTB low optical flux measurement facility Si-SPAD transfer standard Seite 33

34 Comparison: DE (Si-SPAD) calibrated directly against Si-Diode (CMI) and PTB-standard setup Microscope objective Beam splitter Variable Filter Laser 770 nm LOFD Si-SPAD Filter 3 Filter 2 Monitor detector Seite 34

35 Comparison: DE (Si-SPAD) calibrated directly against Si-Diode (CMI) and PTB-standard setup Seite 35

36 Comparison: DE (Si-SPAD) calibrated directly against Si-Diode (CMI) and PTB-standard setup E n U k, SPAD, 2 U k, SPAD PTB CMI k, SPAD, CMI k, SPAD 2 PTB Seite 36

37 Summary Calibration setup and procedure Measurement uncertainty budget Standard measurement uncertainty 0.32 % Improvements: Filter transmission measurements Alignment Standard measurement uncertainty 0.16 % Homogeneity Comparison with CMI-Standard: Consistent results Seite 37

38 Thank you for your attention!

The SIQUTE-project first results towards singlephoton sources for quantum technologies

The SIQUTE-project first results towards singlephoton sources for quantum technologies Stefan Kück (JRP-Coordinator) Physikalisch-Technische Bundesanstalt (PTB), Germany for the SIQUTE-consortium http://www.ptb.de/emrp/siqute-home.html