MPPC-based Quantum Detector Tomography Calibration And Applications

Quantum information technology has developed rapidly over the past few decades and shows great promise that it may exert a significant impact in the 21st century.The rapid development of quantum information science is the primary driving force behind the improvement of single-photon detectors.As a kind of essential single-photon detector,photon-number-resolving detectors,which have a larger dynamic range than conventional single-photon detectors,are able to distinguish the number of incident photons and are expected to be used in quantum information science applications which have higher requirements.In recent years,multi-pixel photon counter(MPPC),with outstanding photon-number-resolving capability,wide dynamic range,insensitivity to the magnetic field,stable operation at room temperature and other great features,has shown excellent performance as a spatial-multiplexed photon-number-resolving detector.The thesis is focused on the quantum calibration and related applications of MPPC.The main research results are as the following:1.To wholly and accurately characterize the photon-number-resolving detection of MPPC,this thesis proposes a scheme to calibrate MPPC with quantum detector tomography(QDT).A pulsed laser calibration platform at two different characteristic wavelengths,791 nm and 523 nm,was built to calibrate MPPC by QDT.The corresponding positive-operator-valued measure(POVM)is reconstructed separately at two wavelengths.The detector is comprehensively and accurately characterized,avoiding the construction of complex models.The photon-number-resolving capability of MPPC was verified by measuring the photon number distribution characteristics of the pulsed laser photon sequences.By further reconstructing the Wigner function of MPPC at these two characteristic wavelengths,the function is negative at the origin,proving that MPPC is a kind of quantum detector.2.To promote the application of MPPC in the detection of magnetic fields of negatively charged nitrogen vacancy(NV)center ensemble in diamond,an attenuated continuous light of 650 nm located in the wavelength range of the NV center phonon sidebands was chosen to calibrate MPPC.The POVMs and Wigner function of MPPC under the random time intervals of photon stream were reconstructed.Theoretical simulations of fluorescence contrast variation of the ODMR spectrum measured by MPPC and Si-APD in the number range of 10-300 NV centers were performed.The results demonstrate that the suitability of MPPC for magnetic field measurements in NV center ensemble with high fluorescence intensity.This thesis further compares the magnetic field detection performance of MPPC with that of silicon avalanche photodiode(Si-APD)in the static(DC)magnetic field measurement experiment of NV center ensemble,and shows that MPPC can be a powerful tool for magnetic field detection of NV center ensemble due to its ability in enhancing measurement contrast in magnetic field measurement under the same conditions.3.In order to break conventional interaction-free measurements' limitation of withouting spectral resolution ability,this thesis investigates a measurement scheme based on interaction-free quantum spectroscopy.In this thesis,frequency-correlation photon pairs are generated by spontaneous parametric down-conversion(SPDC),the heralding photon is around 807.8 nm and the correlated signal photon at 1557.2 nm,respectively.A Mach-Zender interferometer is inserted in the signal photon path,and an under-test sample is placed in one of the arms of the Mach-Zender interferometer.The spectrum information could be obtained by coincidence measurement.This scheme is able to reduce the number of photons interacting with the sample in the spectral measurement and ensures both the distinction between the operating wavelength of the monochromator and the sensitive wavelength of the sample.The high signal-to-noise ratio of the coincidence measurement could be realized based on the non-classical correlation of photon pairs.Moreover,it is promising that MPPC will suppress the generation probability of multi-pair in SPDC-based heralded single-photon sources and enhance the performance of single-photon sources in interaction-free quantum spectroscopy measurements.