【作者】 陈修亮；

【导师】 武愕；

【作者基本信息】 华东师范大学 ， 光学， 2016， 博士

【摘要】 在单光子水平上实现光子数可分辨(PNR)探测是量子光学领域的研究前沿和热点,尤其在量子态制备和量子过程(Quantum process)研究中是不可或缺的关键技术。在量子信息研究中,诸多量子中继和线性光学量子计算方案也都是以PNR探测为基础的。在近红外通信波段,门控盖革模式下的InGaAs/InP雪崩光电二极管(APD)是最常用的单光子探测器件,但是由于门控脉冲产生的尖峰信号的影响,人们很难获得关于雪崩信号的原始信息,以至于无法实现PNR探测的功能。此外,对于PNR探测器的性能评测,除了传统的探测效率、暗计数和后脉冲等参数外,更重要的是完整描述PNR探测过程的量子特征,从而区别于简单的基于光强的经典光电探测过程。量子探测层析技术(QDT)由J.S.Lundeen等科学家于2009年在Nature Phys.上首次提出,通过完整描述探测器的正值算符测度(POVM)矩阵来描述探测器的量子特征。QDT的出现为PNR探测器能否可以真正应用于量子光学的实际系统中提供了可靠的评估依据。本文主要围绕基于InGaAs/InPAPD的PNR探测技术开展研究工作。利用自平衡尖峰信号抑制技术,高保真地采集雪崩信号,通过分析雪崩信号峰值幅度的分布实现了基于InGaAs/InPAPD的直接型PNR探测。在自平衡尖峰信号抑制技术的基础上,发展出了双平衡尖峰信号抑制技术的新方案,进一步压缩尖峰信号的同时提高了雪崩信号的信噪比,有效的提升了 PNR探测的核心性能指标。自主研制了 200 MHz多通道近红外单光子探测器样机,实现了基于InGaAs/InPAPD的时分复用型PNR探测,并利用量子探测层析技术在实验上重新构建了探测器的POVM矩阵。时分复用型PNR探测的实验结果、理论模型模拟结果和利用重新构建的POVM矩阵推算的结果具有很好的吻合度,充分表明QDT准确、可靠的还原了时分复用的PNR探测过程。由重新构建的POVM计算得到的Wigner函数在原点的负值表明此基于InGaAs/InPAPD多通道探测器的时分复用的PNR探测技术方案,具备光子量子态的探测能力,实现了真正的量子探测。本论文的主要创新点如下:1.利用自平衡尖峰信号抑制技术实现了基于InGaAs/InP APD的直接型PNR探测;提出双平衡尖峰信号抑制技术的新方案,雪崩信号的信噪比进一步提高至 11.2dB。2.自主研制了多通道200 MHz近红外单光子探测器样机,4个通道的最高探测效率均高于25%,在探测效率为10%时的暗计数均小于1× 10-5/脉冲。3.利用多通道单光子探测器实现时分复用型PNR探测,并在实验上使用QDT重新构建了 PNR探测器的POVM矩阵。利用重新构建的POVM矩阵推算得到的探测器输出分布的还原度高达99.99%。与重新构建的POVM矩阵对应的Wigner函数在原点的负值验证了 PNR探测器的量子特性,表明该PNR探测器具备光子量子态的探测能力。更多还原

【Abstract】 Photon-number-resolving detection(PNR)at the single-photon level is at the frontier of the research of quantum optics,and it is one of the key techniques in the research of quantum state preparation and quantum processes.Especially,in quantum information,the PNR detection is the basis in some protocols of quantum repeaters and linear optics quantum computing.At present,there are several schemes to realize PNR detection.Among them,InGaAs/InP avalanche photodiode(APD)worked in gated Geiger mode is the most popular devices used to detect single photon in the near-infrared communication band.Normally,as the spike noise is generated by the gate pulse applied on the APD,it is quite difficult to capture the original avalanche signal,which disables the capability of PNR detection except temporal or spatial multi-plexing.But if the spike noise is very well suppressed so that the APD could be operated in the sub-saturation mode.Hence PNR could be achieved with a single APD.In addition,in order to describe the PNR detection in a quantum way,the full quantum characterization of the PNR detection is of great importance in addition to the traditional parameters such as detection efficiency,dark count and afterpulse.The quantum detector tomography was first proposed by J.S.Lundeen et al.in Nature Physics in 2009.The corresponding positive operator-valued measure(POVM)of the PNR detector can be deduced from QDT,which becomes the standard for the quantum characterization of the PNR detector.By QDT,we can evaluate whether the PNR detector can be applied in a real quantum optics system.This thesis is mainly focused on the research of the PNR detection based on InGaAs/InP APD.The self-balanced spike signal cancellation technique was applied to capture the avalanche in less distortion.By analyzing the distribution of the peak amplitude of the avalanche signal,the InGaAs/InP-APD-based PNR detection is realized in a direct way.Then,the double-balanced spike signal cancellation technique was raised to improve the signal-to-noise ratio of the avalanche signal,while further compressing the spike signal,which improves the performance of the PNR detection.In this thesis,a high-speed time-multiplexing infrared PNR detector using a self-developed multi-channel 200 MHz single-photon detector based on InGaAs/InP APDs is demonstrated.And the quantum detector tomography to reconstruct the associated positive operator-value measures is deduced.In order to verify the accuracy of the reconstructed POVM,the result calculated from the reconstructed POVM was compared with the result in the experiment and theoretical simulation,which shows a perfect agreement.The appearance of the negative values of the Wigner function corresponding to the reconstructed POVM indicates the absence of a classical optical analogue.Therefore,the PNR detector is a fundamental quantum detector.The innovations in this paper:1.The PNR detection based on InGaAs/InP APD was realized by using the self-balanced spike signal cancellation technique.The double-balanced spike signal cancellation technique was proposed and demonstrated.The signal-to-noise ratio of the avalanche signal was increased by 11.2 dB.2.A multi-channel 200 MHz single-photon detector based on InGaAs/InP APDs was developed.The detection efficiency of each channel was up to 25%.The dark count of each channel was below/Pulse,while the detection efficiency was 10%.3.A time-multiplexing PNR detector was devised with the multi-channel single photon detector.And the corresponding POVM was experimentally reconstructed by the QDT,The fidelity of the distribution of the detector’s output represented from the reconstructed POVM is 99.99%.更多还原