The properties of a photon counter functioning by stimulated emission---rather than by absorption---of photons in an external field are examined. A possible scheme for such a quantum counter is described, and it is shown that correlation measurements performed with a number of quantum counters correspond to antinormally ordered products of field operators. These correlations, unlike the normally ordered ones, are always positive definite and depend explicitly on the number of radiation modes per unit volume to which the counter is coupled. It is shown that the antinormally ordered correlations carry useful information about the field only when the average photon occupation number per mode is large. A general expression for the probability that the quantum counter registers $n$ counts in a certain time interval is derived and is shown to be related in an interesting way to the corresponding expression for the photoelectric detector. The variance of the probability distribution is evaluated for some simple states of the field.The properties of a photon counter functioning by stimulated emission---rather than by absorption---of photons in an external field are examined. A possible scheme for such a quantum counter is described, and it is shown that correlation measurements performed with a number of quantum counters correspond to antinormally ordered products of field operators. These correlations, unlike the normally ordered ones, are always positive definite and depend explicitly on the number of radiation modes per unit volume to which the counter is coupled. It is shown that the antinormally ordered correlations carry useful information about the field only when the average photon occupation number per mode is large. A general expression for the probability that the quantum counter registers $n$ counts in a certain time interval is derived and is shown to be related in an interesting way to the corresponding expression for the photoelectric detector. The variance of the probability distribution is evaluated for some simple states of the field.

Physical ReviewDec 2, 196685 citations

Second-Order Correlation Measurement for Single-Photon Metrology

Anish Mahavir Bhargav, Abdul Wahid, Samaresh Das +1 more

MAPANAug 9, 20231 citation

Array of superconducting nanowire single photon detectors resolving the number of photons in a weak optical pulse

Nicola Lusardi, A. Geraci, Ronan Gourgues +2 more

Determining the precise number of photons in a weak optical pulse is of crucial importance for imaging, computing or communication applications that use single photons or few photons to increase the performance of classical techniques. Single photons or pair of photons can for instance be used to enhance the resolution of optical imaging techniques or to transmit information with ultimate security using quantum cryptography. In order to maintain this performance gain in such applications, the exact number of photons must be measured and monitored. In this contribution we present a method to measure the number of photons in an optical pulse by using 7 superconducting nanowire single photon detectors. Since a single SNSPD is not sensitive to the number of incoming photons, the optical signal multiplexing is necessary to measure photon correlations among the channels and thus reconstruct the input photons statistics. The readout and counting of the photon arrivals is performed with a fast multi-channel Asynchronous-Correlated-Digital-Counter (ACDC) implemented in the Programmable Logic (PL) of a Xilinx ZYNQ-7020 SoC device. The test of the technique has been performed coupling a weak laser via a fiber multiplexer to an array of individually fiber-coupled detectors.Determining the precise number of photons in a weak optical pulse is of crucial importance for imaging, computing or communication applications that use single photons or few photons to increase the performance of classical techniques. Single photons or pair of photons can for instance be used to enhance the resolution of optical imaging techniques or to transmit information with ultimate security using quantum cryptography. In order to maintain this performance gain in such applications, the exact number of photons must be measured and monitored. In this contribution we present a method to measure the number of photons in an optical pulse by using 7 superconducting nanowire single photon detectors. Since a single SNSPD is not sensitive to the number of incoming photons, the optical signal multiplexing is necessary to measure photon correlations among the channels and thus reconstruct the input photons statistics. The readout and counting of the photon arrivals is performed with a fast multi-channel Asynchronous-Correlated-Digital-Counter (ACDC) implemented in the Programmable Logic (PL) of a Xilinx ZYNQ-7020 SoC device. The test of the technique has been performed coupling a weak laser via a fiber multiplexer to an array of individually fiber-coupled detectors.

IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)Oct 1, 20164 citations

Third-order correlation measurement of ultrashort light pulses

L. Dahlström, Bjorn Kallberg

Optics CommunicationsDec 1, 19718 citations

Measurements of Higher-Order Photon Correlations of Laser Light

Yujiang Qu, Surendra Singh

Springer eBooksJan 1, 19961 citation

Measurement of photon correlations with multipixel photon counters

Dmitry A. Kalashnikov, Leonid A. Krivitsky

Development of reliable photon-number-resolving detectors (PNRDs), devices that are capable of distinguishing 1,2,3… photons, is of a great importance for quantum optics and its applications. A new class of affordable PNRD is based on multipixel photon counters (MPPCs). Here we review results of experiments on using MPPCs for direct characterization of squeezed vacuum (SV) states, generated via parametric downconversion. We use MPPCs to measure the second-order normalized intensity correlation function (g(2)) and directly detect the two-mode squeezing of SV states. We also present a method of calibration of crosstalk probability in MPPCs based on g(2) measurements of coherent states.Development of reliable photon-number-resolving detectors (PNRDs), devices that are capable of distinguishing 1,2,3… photons, is of a great importance for quantum optics and its applications. A new class of affordable PNRD is based on multipixel photon counters (MPPCs). Here we review results of experiments on using MPPCs for direct characterization of squeezed vacuum (SV) states, generated via parametric downconversion. We use MPPCs to measure the second-order normalized intensity correlation function (g(2)) and directly detect the two-mode squeezing of SV states. We also present a method of calibration of crosstalk probability in MPPCs based on g(2) measurements of coherent states.

arXiv:1408.0059Journal of the Optical Society of America BSep 23, 201411 citations

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counts in a certain time interval is derived and is shown to be related in an interesting way to the corresponding expression for the photoelectric detector. The variance of the probability distribution is evaluated for some simple states of the field.