Multi-Channel Single Photon Detection And Application

Single photon detector is a kind of super sensitive photoelectric converter, which can detect the minimum energy of light-a photon. It plays an important role in the fields of physics, chemical, biological fluorescence, astronomical mapping, quantum communication and remote sensing. The signal-to-noise ratio (SNR) deteriorated rapidly that photon signal couldn’t be detected because of the daylight background noise. Daylight noise was particularly prominent in the practical applications of optical laser communication and mapping, and became the main technical bottleneck which limit the application of single photon detection technology in these fields. Although silicon avalanche diode (Si APD) developed well which got high detection efficiency at wavelength from 400 nm-1000 nm, it still had low saturation count rate, less of resolving photon number and low detection efficiency at solar-blind wavelength. It needed more deep research to reduce daylight background noise.In this paper, we proposed multi-channel single photon detection to realize photon number resolving which could improve saturation count rate and reduce the impact of background noise. Based on FPGA controlling, the multiplex Si APDs were packaged in the same module and the FPGA generated the Quench and Reset signal to control Si APD. Moreover, the FPGA supplied data acquisition and processing which was responded by APD and realized photon number resolving.Meanwhile, solar-blind wavelength light couldn’t reach the near-Earth environment, so solar-blind detector worked like in the dark room environment which could reduce the impact of daylight noise. In this paper, we focus on the research of single photon detector based on APD. We demonstrated an optical structure to improve the detection efficiency of Si APD in ultraviolet wavelength. Under optimal condition, the efficiency could be improved from 4.5% to above 10% without changing fabrication technology of Si APD.In this paper, we used multi-channel single photon detection module to demonstrated free space laser communication and this technology showed advantage of multi-channel single photon detection equipped with integrated single photon detection and photon number resolving in reducing background noise. It solved application limitation in the fields of Laser 3D imaging and free space Laser communication.