A novel technique for photon correlation measurements, based on the excitation of a resonant system by photon-detector single pulses, analog/digital sampling, and deconvolution, has been developed and analyzed experimentally and by computer simulations. The measured correlation function is expressed by a convolution of the true photon correlation function of the optical field and a well-defined, noiseless resonator correlation function. The effect of detector statistics is reduced to the contribution of two integral parameters—the total single-pulse charge and the jitter of single-pulse centers. Good performance of this technique is demonstrated at high photon rates and resolutions, where the well-known photon-counting or single-quantum methods are ineffective. The novel technique offers linear recording of photocount time series without dead-time effects. The temporal resolution is defined by the sampling step of the analog/digital converter. The retrieval error does not exceed 1 to 3% at count rates higher than 1 GHz and single-pulse durations larger than the resolution cell. This technique can be effectively applied in photon correlation measurements of high dynamic optical fields.
A novel technique for photon correlation measurements, based on the excitation of a resonant system by photon-detector single pulses, analog/digital sampling, and deconvolution, has been developed and analyzed experimentally and by computer simulations. The measured correlation function is expressed by a convolution of the true photon correlation function of the optical field and a well-defined, noiseless resonator correlation function. The effect of detector statistics is reduced to the contribution of two integral parameters—the total single-pulse charge and the jitter of single-pulse centers. Good performance of this technique is demonstrated at high photon rates and resolutions, where the well-known photon-counting or single-quantum methods are ineffective. The novel technique offers linear recording of photocount time series without dead-time effects. The temporal resolution is defined by the sampling step of the analog/digital converter. The retrieval error does not exceed 1 to 3% at count rates higher than 1 GHz and single-pulse durations larger than the resolution cell. This technique can be effectively applied in photon correlation measurements of high dynamic optical fields.
High-order photon correlations of light fields are important for characterizing the quantum nature. Since Hanbury Brown and Twiss conducted the pioneering experiments in the 1950s, the HBT effect has inspired extensive research on high-order photon correlation in quantum optics, quantum information, and quantum imaging. The Single-photon counting module is one of the most widely used single-photon detectors. Due to its high detection efficiency and low dark counts in the visible and near-infrared region, it is reasonably chosen for basic research on quantum mechanics. Many researches have demonstrated that the maximum value of second-order photon correlation g(2)(τ) at zero delay (τ = 0) can be used to distinguish different light fields. Therefore, the HBT scheme containing two single photon detectors have been widely used in many advanced studies, such as space interference, ghost imaging, single photon detection with high efficiency, etc. However, higher-order photon correlations g(n) (n > 2) can reveal more measurable characteristics of light fields, such as information about the non-Gaussian scattering process, the skewness and kurtosis of photon number distribution, etc. When the extended HBT scheme is used to measure higher-order photon correlations, the experimental conditions including quantum efficiency and background noise greatly affect the photon correlation measurement. The influences of the counting rate and resolution time of the detection system on the measurements are also very important and cannot be ignored. Therefore, the comprehensive considering of various influence factors is necessary for accurately measuring the high-order photon correlations and also a challenge. In this paper, we present a method based on double Hanbury Brown-Twiss scheme for the accurate measuring of high-order photon correlations g(n) (n > 2). The system consists of four single photon counting modules and is used to detect and analyze the joint distribution probability of temporal photon correlation. Considering the effects of the background noise and overall efficiency, theoretically, we analyze the correlations of the third- and fourth-order photon with the incident light intensity, squeezing parameter and photon number respectively for thermal state, coherent state, squeezed vacuum state, and Fock state. Meanwhile, experimentally we study the influences of resolution time and counting rate on correlations of the coherent state and thermal state with third- and fourth-order photon. On condition that the resolution time is 210 ns and the counting rate is 80 kc/s, the correlations of third and fourth-order photon with the thermal state at zero time delay are accurately measured, and the relative statistical deviations of the measured vales from the theoretical values are 0.3% and 0.8%, respectively. In addition, the third- and fourth-order photon correlations of the thermal state at different delay times are also observed. It is demonstrated that the high-order photon correlations of light fields are measured accurately by comprehensively analyzing various influencing factors. This technique provides a promising and useful tool to investigate quantum correlated imaging and quantum coherence of light fields.
We present a detailed discussion of a recently demonstrated experimental technique capable of measuring the correlation function of a pulsed light source with picosecond time resolution. The measurement involves a streak camera in single photon counting mode, which is modified such that a signal at a fixed repetition rate, and well defined energy, can be monitored after each pulsed laser excitation. The technique provides further insight into the quantum optical properties of pulsed light emission from semiconductor nanostructures, and the dynamics inside a pulse, on the sub-nanosecond time scale.
A method to measure the correlation function of a biphoton field, which does not require single-photon detectors and photocount coincidence schemes, has been proposed and experimentally approved. It is based on the statistical analysis of current data from analog detectors. On an example of the operation of a scheme with analog photomultiplier tubes in the signal and idler channels of degenerate parametric down conversion, it has been shown that this new approach allows one to obtain correlation function values coinciding with the results of the standard photon counting technique. It has been shown how the absolute values of photon numbers and radiation power in the signal channel of the down conversion scheme are determined from the measured correlation function. Analog detection can expand the spectral and dynamic ranges of electromagnetic radiation for the application of quantum optic technologies. A method for the reference-free measurement of the spectral sensitivity of an analog photosensor module has been demonstrated as the first example of application.
High temporal resolution detection for time-correlated single-photon counting (TCSPC) is critical for a broad range of applications, such as sensing, bio-imaging and quantum information. To harness non-classical advantages, high temporal resolution TCSPC is necessary to capture the unique properties of quantum entanglement, in which the precise time delays between two photons are used to reconstruct the biphoton distribution. However, current state-of-the art, high-resolution TCSPC systems, such as superconducting nanowires, have large footprints and require cryogenic cooling to liquid helium temperatures. They are not well equipped to be conveniently mounted on a satellite or transported within a health care facility. Small footprint, simple, low energy consuming single photon detection systems are therefore needed in order for high temporal resolution TCSPC applications to move beyond the research laboratory. In this direction, we demonstrate a proof-of-concept experiment for improving the temporal resolution of single-photon and biphoton detection schemes that is simple, fiber-based, and readily chip integrable. The principle relies on electrooptic gating of fast single-photon and biphoton signals using a high-speed RF pulse which drives an electro optic intensity modulator. As such, the instrument response function (IRF) of the detection scheme takes on the temporal profile of the electro-optic gate. Experimentally, we improve the IRF of our detection scheme from ~1.54 ns to <100 ps, allowing high resolution detection of ultrafast single photon TCSPC signals as well as to observe nonlocal dispersion cancellation effects in ultrafast biphoton distributions. This technique could allow for practical and simplified access to rapid temporal dynamics at the single photon scale.
A novel high-throughput second-order correlation measurement system is developed that records and makes use of all the arrival times of photons detected at both start and stop detectors. This system is suitable, particularly for a light source having a high photon flux and a long coherence time, since it is more efficient than conventional methods by an amount equal to the product of the count rate and the correlation time of the light source. We have used this system in carefully investigating the dead time effects of detectors and photon counters on the second-order correlation function in the two-detector configuration. For a nonstationary light source, a distortion of the original signal was observed at high photon flux. A systematic way of calibrating the second-order correlation function has been devised by introducing the concept of an effective dead time of the entire measurement system.
Abstract We present an experimental technique that can accurately measure the high-order photon correlations of various light fields based on double Hanbury Brown–Twiss scheme. The system consists of four conventional binary response single-photon counting modules which are non-photon-number-resolving detectors. We theoretically analyze the effects of the experimental conditions on the high-order photon correlations of coherent, chaotic thermal, Fock and squeezed vacuum states with considering the overall efficiency and background noise. In experiment, we determine the proper resolution time from 2 9 = 512 ns to 2 11 = 2048 ns and counting rate from 10 kc s −1 to 100 kc s −1 for characterizing the exact second-, third- and fourth-order photon correlations of chaotic thermal state. At complete time delays, we also observe the third- and fourth-order photon correlations of chaotic thermal state, with the maximum high-order correlation values of 5.99 ± 0.02 and 23.9 ± 0.2 respectively, which are in good agreement with the theoretical values of 6 and 24. The demonstrated experimental technique with high accuracy is a promising tool for investigating quantum optical coherence and ghost imaging.