【作者】 鄢秋荣；

【导师】 赵宝升；

【作者基本信息】 中国科学院研究生院（西安光学精密机械研究所） ， 物理电子学， 2012， 博士

【摘要】 近年来，时间相关单光子计数（TCSPC）技术取得了很大的进步，发展成一种快速、多维的光学记录技术,在荧光寿命成像、扩散光学层析、时间分辨荧光显微、激光雷达和超灵敏时间分辨光谱测量中获得了应用。本文主要针对当前时间相关单光子计数技术用于成像探测或光谱测量时,必须利用高精密的光机扫描元件，由于扫描时间长，成像的实时性、时间分辨、空间分辨率不高等问题，提出自主研制具有面阵结构的微通道板（MCP）位敏阳极探测器，光子到达时间和位置同步测量电子学系统和数据处理软件，实现光子到达时间和位置的连续、同步测量，探索在时间分辨光子计数成像，随机数提取等方面的应用。主要研究内容及成果如下：（1）调研了时间相关单光子计数技术的原理、国内外研究进展及在相关领域的应用。对单光子探测器、前置放大技术、电荷测量技术、定时技术及时间数字转换技术等TCSPC系统的关键技术进行了详细的分析。提出了基于MCP位敏阳极探测器的光子到达时间和位置同步测量方案；（2）设计并研制了MCP位敏阳极探测器。探测器采用电荷直接收集型结构；MCP采用“V”型或“Z”型级联；阳极采用基于电荷分配技术的游标阳极或楔条形阳极；探测器前端电子学采用电荷灵敏前放和整形主放；（3）设计并研制了光子到达时间和位置同步测量电子学系统。提出并实现一种光子序列到达时间的连续、高精度测量方法。采用粗时间测量和细时间测量相结合的方法测量光子序列相对于同一起始时刻的时间。粗时间的测量采用对高稳定度时钟进行计数的方式，细时间的测量采用基于FPGA进位链的高精度时间数字转换。提出并实现利用光子到达定时信号来实现光子到达时间和位置同步测量的方法,光子到达定时信号一方面用于确定光子的到达时刻，另一方面经过延时后作为触发信号，触发多路峰值保持采集进行采集。多路脉冲幅度采集采用峰值保持后触发采集的方式，每路单光子脉冲只采集一个点；光子到达定时方法为先对多路脉冲进行求和，然后采用恒比定时（CFD）方法产生光子到达定时信号，并增加了阈值甄别的功能。采用USB2.0接口和内存切换的方式实现将光子到达时间和位置数据连续传输到计算机。经电子学性能测试结果表明，所设计电子学系统的脉冲峰值采集的精度为20mV,定时精度为0.95ns，时间间隔测量的精度为500ps，死时间为100ns,最大平均计数率为2.67Mcps,最长记录时间为6.11小时；（4）利用基于MCP位敏阳极探测器的光子到达时间和位置同步测量系统，搭建了时间分辨光子计数成像探测系统。推导了基于MCP位敏阳极探测器的时间分辨光子计数成像理论模型。利用VC6.0开发计算机软件，实现数据采集、数据缓存、数据预处理、数据分析、阳极解码和图像合成等功能。为了提高成像分辨率，对游标阳极解码算法进行了改进。实验中获得极微弱光的时间分辨光子计数图像。经测试,位敏阳极采用游标阳极时空间分辨率优于100μm，位敏阳极采用楔条形阳极时空间分辨率优于80μm，光子到达时间分辨优于1.53ns；（5）利用基于MCP楔条形阳极探测器的光子到达时间和位置同步测量系统，搭建了基于光子时空间随机性的光量子随机源。在光子到达空间随机性方面，提出光子到达空间编码的随机位提取方法。在光子到达时间随机性方面，提出三种随机位的提取方法，一是利用等时间间隔内光子的奇偶性来提取随机位；二是利用相邻到达光子时间间隔大小来提取随机位；三是光子到达时间编码随机位提取法。运用国际通用随机性测试软件ENT对上述四种随机数提取方法所获得随机系列进行随机性测试，测试结果表明上述几种方法所提取的二进制随机序列的随机性非常好且不需要后续处理，完全符合真随机数的标准。更多还原

【Abstract】 Currently, Time-correlated single photon counting technology (TCSPC) has madea great progress，has been developed into a fast, multi-dimensional optical recordingtechnology and widely used in fluorescence lifetime imaging, diffuse opticaltomography, time-resolved fluorescence microscopy, laser radar and ultra-sensitivetime-resolved spectral measurements. The high-precision optical scanningcomponents are required when TCSPC used for imaging detection or spectralmeasurements. Due to long scan time, real-time imaging is limited, and the time andspatial resolution is not high. This paper focused on this problem, and proposed todeveloped MCP position sensitive anode detector with array structure, the electronicssystems, and the data processing software to achieve continuous，simultaneousmeasurement of arrival time and location of single photon, and explore the applicationin the time-resolved photon counting imaging, the pulse profile detection of veryweak X ray and the random number extraction. The main research contents andresults are as follows:(1) The principle of TCSPC, research advances and applications in related fields areinvestigated. The key technology of TCSPC system, including single-photon detector,pre-amplification techniques, charge measurement techniques, timing and time-digitalconverter techniques were described in detail. The program of simultaneousmeasurement system of arrival time and location of photon based on MCP positionsensitive anode single photon detector is proposed;(2) The MCP position sensitive anode single detectors are designed and developed.The detector is designed as charge directly collected structure, use "V" or the "Z"-typecascade MCP to multiply electron, and read out by charge distribution anode, theVernier anode and WSZ anode. Charge-sensitive preamplifier and shaping amplifierare chose as the front end electronics;(3) The electronic system used for simultaneous measurement of arrival time and location of single photon is designed and developed. In the electronic system, thearrival times of photon sequence relative to a common start time is measured bycombing coarse time and fine time. A high stability OCXO clock is counted tomeasure the coarse time and a high resolution FPGA-based carry chain TDC is usedto measure the fine time. The photon arrival timing signal is used to set upsynchronization, on the one hand the timing signal is used to determine the arrivaltime of photon, on the other and, the timing signal trigger peak acquisition after adelay. The amplitudes of multi-channel pulse are measured by triggering sample afterpeak hold and each single-photon pulse sample only one point. The timing circuit ofarrival photon firstly sums up multi-channel pulses into one pulse, and then generatestiming signal by the constant fraction timing methods with threshold discriminationfunction. The data of photon arrival times and locations is transmitted to computer bymemory switching technology and an usb2.0interface. The electronic properties testresults shows that the multi-channel pulse peak acquisition accuracy is20mV, thetiming accuracy of photon arrival is0.95ns, time measurement accuracy is500ps, thedead time of electronic system is100ns and the maximum average count rate is2.67Mcps, maximum recording time is6.11hours;(4) A time-resolved photon counting imaging system is set up using thesimultaneous measurement system of arrival time and location of photon based onMCP position sensitive anode detector. Time-resolved photon counting imagingtheoretical model is derived based on the MCP position sensitive anode detector.Software has been developed to achieve the function including data acquisitioncontrol, data preprocessing, data analysis, position decoding, and image synthesis.The time-resolved image of the very weak optical radiation can be reconstructed byimage processing. According to test, the space resolution is superior to100mμ withVernier anode and80mμ with WSZ anode, time resolution is superior to1.53ns；(5) An optical quantum random number generator is set up using the simultaneousmeasurement system of arrival time and location of photon based on MCP WSZanode detector. A space encoding method is proposed to extract random number basedon the space randomness of arrival photon. Three different kinds of method are proposed to extract random number based on the time randomness of arrival photon.First, the number of photons detected in parity time interval is proposed to extractrandom number. Second, continuously comparing the time intervals between twoadjacent detected photons is proposed to extract random number. Third, a kind of timeencoding method is proposed to extract random number. The random numbersgenerated by above four methods are tested by software ENT. Test results show all ofrandom numbers have a good randomness, do not require post-processing and fullymeet the standards of true random numbers.更多还原