scholarly journals Reducing $g^{(2)}(0)$ of a parametric down-conversion source via photon-number resolution with superconducting nanowire detectors

2022 ◽  
Author(s):  
Santiago Sempere-Llagostera ◽  
Guillaume Thekkadath ◽  
Raj Patel ◽  
W Steven Kolthammer ◽  
Ian Walmsley
Keyword(s):  
Photon Number ◽  
Parametric Down Conversion ◽  
Down Conversion ◽  
Superconducting Nanowire

scholarly journals Reducing g(2)(0) of a Parametric Down-Conversion Source via Photon-Number Resolution with Superconducting Nanowire Detectors

2021 ◽  
Author(s):  
S. Sempere-Llagostera ◽  
G. S. Thekkadath ◽  
R. B. Patel ◽  
W. S. Kolthammer ◽  
I. A. Walmsley
Keyword(s):  
Photon Number ◽  
Parametric Down Conversion ◽  
Down Conversion ◽  
Superconducting Nanowire

scholarly journals Quantum-enhanced interferometry with large heralded photon-number states

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
G. S. Thekkadath ◽  
M. E. Mycroft ◽  
B. A. Bell ◽  
C. G. Wade ◽  
A. Eckstein ◽  
...  
Keyword(s):  
Photon Number ◽  
Optical Loss ◽  
High Gain ◽  
Phase Sensitivity ◽  
Entangled Photons ◽  
Fundamental Limits ◽  
Parametric Down Conversion ◽  
Photonic States ◽  
Quantum Phenomena ◽  
Down Conversion

Abstract Quantum phenomena such as entanglement can improve fundamental limits on the sensitivity of a measurement probe. In optical interferometry, a probe consisting of N entangled photons provides up to a $$\sqrt{N}$$ N enhancement in phase sensitivity compared to a classical probe of the same energy. Here, we employ high-gain parametric down-conversion sources and photon-number-resolving detectors to perform interferometry with heralded quantum probes of sizes up to N = 8 (i.e. measuring up to 16-photon coincidences). Our probes are created by injecting heralded photon-number states into an interferometer, and in principle provide quantum-enhanced phase sensitivity even in the presence of significant optical loss. Our work paves the way toward quantum-enhanced interferometry using large entangled photonic states.

scholarly journals Non-classical Signature of Parametric Fluorescence and its Application in Metrology

2014 ◽  
Vol 14 (4) ◽  
pp. 227-236 ◽  
Author(s):  
M. Hamar ◽  
V. Michálek ◽  
A. Pathak
Keyword(s):  
Numerical Simulations ◽  
Photon Number ◽  
Theoretical Background ◽  
Iccd Camera ◽  
Parametric Down Conversion ◽  
Light Beams ◽  
Down Conversion ◽  
Theoretical Results ◽  
Multimode Beams

Abstract The article provides a short theoretical background of what the non-classical light means. We applied the criterion for the existence of non-classical effects derived by C.T. Lee on parametric fluorescence. The criterion was originally derived for the study of two light beams with one mode per beam. We checked if the criterion is still working for two multimode beams of parametric down-conversion through numerical simulations. The theoretical results were tested by measurement of photon number statistics of twin beams emitted by nonlinear BBO crystal pumped by intense femtoseconds UV pulse. We used ICCD camera as the detector of photons in both beams. It appears that the criterion can be used for the measurement of the quantum efficiencies of the ICCD cameras.

Triggering parametric-down conversion-based quantum key distribution via radiation field

2020 ◽  
Vol 18 (06) ◽  
pp. 2050037
Author(s):  
Tchoffo Martin ◽  
Tene Alain Giresse ◽  
Djebayole Mimbe III Yannick
Keyword(s):  
Radiation Field ◽  
Quantum Key Distribution ◽  
Secure Communication ◽  
Photon Number ◽  
Threshold Detector ◽  
Decoy State ◽  
Safety Distance ◽  
Parametric Down Conversion ◽  
Down Conversion ◽  
Photon Source

We discuss the influence of radiation field on the secure key size and the maximum safety distance during QKD by using a set of photons produced via a spontaneous parametric-down conversion (SPDC) photon source. Four implementations that use multiple-photons and decoy states are discussed, these include nondecoy state, infinite active decoy state, passive decoy state with threshold detector and passive decoy state with perfect photon-number resolving detector. Results show that the radiation field significantly improves both the secure key size and the maximum secure communication distance. Therefore, the radiation field is found to be a good candidate to reduce unwanted interactions of photons with the quantum channel and hence, to increase the secure key rate and the maximum safety distance between legitimate users.

scholarly journals Analysis of the Spatial Properties of Correlated Photon in Collinear Phase-Matching

Photonics ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 12
Author(s):  
Lin Yin ◽  
Jianjun Li ◽  
Wenchao Zhai ◽  
Maopeng Xia ◽  
Youbo Hu ◽  
...  
Keyword(s):  
Photon Number ◽  
Divergence Angle ◽  
Phase Matching ◽  
Cmos Camera ◽  
Theoretical Simulation ◽  
Spatial Properties ◽  
Measurement Results ◽  
Parametric Down Conversion ◽  
Theoretical Reasoning ◽  
Down Conversion

In this paper, the spatial properties of correlated photon in collinear phase-matching in the process of spontaneous parametric down conversion (SPDC) are researched. Based on the study of the phase-matching angle, non-collinear angle, and correlated photon wavelength, a theoretical model of non-collinear angular variation is derived, which can be used to estimate and predict the width of the correlated photon ring. The experimental measurement is carried out with CMOS camera, and the measurement results are consistent with the theoretical simulation results, which verifies the rationality of theoretical reasoning. Meanwhile, the change of the correlated photon divergence angle outside the crystal is studied, the closer the wavelength is to the degenerate, the smaller the measurement value of the divergence angle, which is agreement with the theoretical simulation. The results of the study play a reference role in the evaluation of the spatial properties of correlated photon and lay a foundation for the measurement of the correlated photon number rate and the calibration of a photodetector.

scholarly journals Photon Number Statistics of Multimode Parametric Down-Conversion

2008 ◽  
Vol 101 (5) ◽  
Author(s):  
M. Avenhaus ◽  
H. B. Coldenstrodt-Ronge ◽  
K. Laiho ◽  
W. Mauerer ◽  
I. A. Walmsley ◽  
...  
Keyword(s):  
Photon Number ◽  
Parametric Down Conversion ◽  
Down Conversion
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