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Mauro Rajteri Divisione OTTICA

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1 Mauro Rajteri Divisione OTTICA
Panoramica INRIM Rivelare i fotoni e la loro statistica con i Transition-Edge Sensors (TESs) Mauro Rajteri Divisione OTTICA Mauro Rajteri, 12/06/2013 Panoramica INRIM

2 Introduction Photon: also called Light Quantum, minute energy packet of electromagnetic radiation. The concept originated (1905) in Einstein’s explanation of the photoelectric effect (enc. Brittanica) Photon counting: average count rate  intensity of the light beam but actual count rate fluctuates from measurement to measurement.

3 Photon statistics Coherent light & constant intensity: 3.1

4 Poissonian statistics

5 Poissonian statistics

6 Single Photon detectors
"Classical" Single photon detector Photon source Photon number resolving (PNR) detector

7 Transition-Edge Sensors (TESs)
TES: a superconducting film operated in the temperature region between the normal and the superconducting state DTc ~ 1 mK  high sensitive thermometer Ibias t (s) I R Ites Workig Point Tc ~ 100 mK T Rbias<< Rtes DT DR @ Voltage bias  DI

8 Transition-Edge Sensors (TESs)
TES: a superconducting film operated in the temperature region between the normal and the superconducting state DTc ~ 1 mK  high sensitive thermometer Ibias t (s) I R 1 ph Ites Workig Point Tc ~ 100 mK T Rbias<< Rtes DT DR @ Voltage bias  DI

9 Transition-Edge Sensors (TESs)
TES: a superconducting film operated in the temperature region between the normal and the superconducting state DTc ~ 1 mK  high sensitive thermometer 2 phs Ibias t (s) I Tc ~ 100 mK R Ites Working Point T Rbias<< Rtes DT DR @ Voltage bias  DI

10 Transition-Edge Sensors (TESs)
Bilayer – proximity effect Ti=24 nm, Au=54 nm Tc =121 mK ∆Tc = 2 mK Rn = Ω 10 µm X10 µm 20 µm X 20 µm

11 TES: thermal model g= thermal conductance
Thermal bath Substrate Superconductor - ph Superconductor - e gsub-b gph-sub ge-ph Tb Tsub Tph Te Pe Pinc Ps g= thermal conductance K = constant: material and geometry dependent n = constant: depends on the dominant thermal coupling mechanism For T < 1K  electron-phonon decoupling  n  5

12 Intrinsic Energy Resolution
TES: theory Intrinsic Energy Resolution ∆EFWHM is proportional to the operating temperature Tc Effective TES response time etf is lower than th if /n >1

13 TES: optical alignment
Gaussian beam: w0=4.7/5.6 l=1.3/1.55 mm (TES 20 x 20 mm) 2w0 2w ~19÷ 25 mm 2w z ~ 125 m 1mm 0,5 mm back off 5 mm 3 mm 0,25 1,5 mm 0.8 mm Silicon Silicon V-groove with fiber array Cu bracket acc ~ ÷

14 TES: optical losses Optical coupling fiber-TES
Reflection and transmission of superconducting film  Antireflection coating or optical cavity Substrate 2 layers R(1550)=0.018% a-Si3N4:Hy (low reflection index) a-SiH (high reflection index)

15 Electronics & data aquisition
TES: photon counting Laser Electronics & data aquisition DITES Optical fiber Attenuator INRIM: TES module SQUID current sensors (PTB)

16 TES: photon counting

17 TES: photon counting

18 TES: pulse analysis Wiener filter: 2x improvement on E 1 (a) 2 3 4 5
Noisy: ΔE = 0.46 eV Wiener filter: 2x improvement on E 1 (a) 2 Wiener: ΔE = 0.22 eV 3 4 5 (b) D. Alberto, et al, Optical Transition-Edge Sensors Single Photon Pulse Analysis, IEEE Trans. Appl. Supercond., 21 , 285 – 288 (2011)

19 TES: photon counting

20 TES: photon counting phs 20X20 μm2 =1570 nm
L. Lolli, et al. J. Low Temp. Phys., vol. 167, pp , 2012.

21 TES: QE absolute calibration
w p i s P A R M E T I C Y S L O U N Absolute Q u a n t m f c e y Detector to be Calibrated “Herald” Detector NC N1 N2 Klyshko Drawback: Klyshko's technique is not able to exploit the PNR ability of the detector Proposal and demonstration of an absolute technique for measuring quantum efficiency, based on an heralded single photon source, but exploiting the PNR ability of the detector A. Avella et al OPTICS EXPRESS p

22 TES: QE absolute calibration
Probability of observing i photons per heralding count in the presence of the heralded photon in the absence of the heralded photon (i.e. of observing i “accidental” counts) The probability of observing 0 photons per heralding count : Non detection & No accidental False her.& No accidental “Total” Quantum Efficiency of the PNR detector optical and coupling losses   detector proper Quantum Efficiency  Probability of having a True Heralding Count (not due to stray-light or dark counts)

23 TES: QE absolute calibration
The probability of observing i photons per heralding count From each a value of “Total” Quantum Efficiency can be estimated  Consistency Test From the probability of 0 From the probability of i Hp of the Klyshko’s Technique: multiphoton PDC events negligible

24 TES: QE absolute calibration
TES detection system HWP IF1 IF2 NLC a b DET1 PDC single photon source Pump source

25 TES: QE absolute calibration
PUMP total quantum efficiency DET1 6 Repeated measurements each 5 hr. long >5 106 counts Heralded Accidental @ 807 nm prob. of true heralding counts

26 TES: POVM tomography “n”
POVM provides the description of the measurement process “n” Prob. of output “n”

27 TES: POVM tomography “n”
POVM provides the description of the measurement process “n” Prob. of output “n”

28 TES: POVM tomography “n”
POVM provides the description of the measurement process “n” Prob. of output “n” : Prob. of having output “n” with m photons as input

29 TES: POVM tomography Simplest Solution: Fock state source

30 TES: POVM tomography Simplest Solution: Fock state source

31 TES: POVM tomography Simplest Solution: Fock state source
Affordable Solution: Coherent source [Lundeen et al., Nat. Phys 5, 27 (2009)]

32 TES: POVM tomography Coherent source Pulsed laser source
Experiment with a TES 1570 nm

33 TES: POVM tomography Coherent source Pulsed laser source
Experiment with a TES

34 TES: POVM tomography Coherent source Pulsed laser source
Experiment with a TES

35 TES: POVM tomography Coherent source   =5.1% Linear detection model
  =5.1% G. Brida et al New Journal of Physics 14 (2012)

36 within the Executive Programme Italy-Japan 2010-2012
Fast TES Joint Projects for the exchange of researchers within the Executive Programme Italy-Japan Alignment: ADR cold finger

37 Fast TES

38 @ 500 kHz means 3.65x106 photons/s (473 fW)
Fast TES TiAu TES Tc=301 mK 73 phs =1535 nm @ 500 kHz means 3.65x106 photons/s (473 fW) QE  50 %

39 Fast TESs review

40 TES: High energy resolution
Rn=0.45  45nm Au+45nm Ti 10 mm x 10 mm Tc=106 mK Ce=0.35fJ/K

41 TES: High energy resolution
teff = 3.8 ms DE = (0.113 ± 0.001) eV (Submitted to APL)

42 Impedance

43 Conclusions TES  Photon number resolving detectors 
 Wavelength range: UV-IR   Quantum efficiency:50%90%   Dark counts: background limited   Count rate:  1 MHz   Working temperature: < 1K 

44 Chi fa cosa Sviluppo  Taratura Applicazioni  Collaborazioni 
Fabbricazione: C. Portesi, E. Monticone Caratterizzazione : E. Taralli, L.Lolli , E. Monticone, M. Rajteri (criogenica, elettrica e ottica) E. Taralli, L. Callegaro (impedenza) Sviluppo  Taratura Applicazioni Ottica quantistica: A. Avella,G. Brida, L. Ciavarella, I. Degiovanni, M. Genovese, M. Gramegna, M.G. Mingolla,F. Piacentini, M.L. Rastello, P. Traina Collaborazioni  J. Beyer, D. Fukuda, T. Numata, M.G.A. Paris, M. White, G. Cantatore, G. Ventura

45 Metrology with/for NEMS
Finanziamenti -Fotorivelatori superconduttivi ad elettroni caldi per il VIS-IR -Realizzazione di STJ come rivelatori in regime di conteggio di fotoni per applicazioni astrofisiche E45 ( ) Rivelatori superconduttivi a transizione di fase per conteggio di singoli fotoni Quantum Candela ( ) Progetto premiale P5 ( ) Oltre I limiti classici della misura NEW08 MetNEMS ( ) Metrology with/for NEMS

46 Grazie per l’attenzione!


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