基于压缩采样的光子计数相干探测技术研究

Current photon counting coherent detection methods mainly utilize the photon-number-resolving detector to overcome the influence of dead-time effect on spectrum recognition of coherent beat signal. Their working wavelength and application range are restricted by the photon-number-resolving detector. Here, a novel method about photon counting coherent detection based on compressive sampling is proposed, which creatively uses compressive sampling to break through the limitation of Nyquist sampling frequency. In this case, the influence of dead-time effect on spectrum recognition can be overcome, which makes it possible to implement coherent detection using GM-APD cell detector, and reduce dependence on the photon-number-resolving detector. In general, the photon-number-resolving detector can only be used to perform Doppler measurements previously. However, with the compressive sampling framework, Doppler imaging can be performed directly (for array structure detectors, such as GM-APD array), or data update-rate can be enhanced (for macro-pixels structure detectors, such as SiPM). Such superiority will greatly improve the application range for photon counting coherent detection system.

现有的光子计数相干探测方法主要利用光子数分辨探测器来间接地克服死时间效应对相干拍频信号频谱识别的影响，其工作波长和应用范围受到光子数分辨探测器的制约。本项目提出基于压缩采样的光子计数相干探测新方法，巧妙地运用压缩采样技术突破奈奎斯特采样频率的限制，进而克服死时间效应对相干拍频信号频谱识别的影响。如此一来，采用GM-APD单元探测器即可实现相干探测，使光子计数相干探测摆脱对光子数分辨探测器的依赖。此前采用光子数分辨探测器才能进行多普勒测速，然而在本项目的压缩采样框架下，光子数分辨探测器可直接进行多普勒成像（针对阵列结构探测器，如GM-APD阵列），或者提高数据更新率（针对微元结构探测器，如SiPM硅光电倍增管），极大地提高了探测系统的应用价值。

光学相干探测技术具有分辨率高、信息量大等显著优势而被广泛应用于激光雷达、光通信、光学相干层析成像等领域。本项目将光子计数技术引入相干探测，建立了基于压缩采样的光子计数相干探测方法，突破了宽带光子计数相干探测关键技术，搭建了光子计数相干探测仿真系统和实验系统，在实现单光子灵敏度的同时，能够实现宽带频谱感知和高分辨率三维成像。本项目所特有的带宽高灵敏度优势是传统相干探测方法无法比拟的，能够用于高速运动目标及微动目标探测识别，有望在国民经济和国防安全领域发挥作用。