光子数可分辨探测及其量子探测层析研究

发布时间：2018-08-21 20:08

【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。
[Abstract]:The realization of photon number discernible (PNR) detection at the single photon level is the research frontier and hotspot in the field of quantum optics, especially in the preparation of quantum states and the study of quantum process (Quantum process). In the study of quantum information, many quantum relay and linear optical quantum computing schemes are also based on PNR detection. In the near infrared communication band, the InGaAs/InP avalanche photodiode (APD) in gate mode is the most commonly used single photon detector, but it is difficult to obtain the original information about the avalanche signal because of the effect of the spike signal produced by the gated pulse. It is impossible to realize the function of PNR detection. Besides the traditional parameters such as detection efficiency, dark count and post-pulse, it is more important to describe the quantum characteristics of the PNR detection process. Therefore, it is different from the simple classical photoelectric detection process based on light intensity. Quantum detection chromatography (QDT) was developed by J.S.Lundeen and other scientists in Nature in 2009. It is proposed for the first time that the quantum characteristics of the detector can be described by describing the positive operator measure (POVM) matrix of the detector completely. It provides a reliable evaluation basis for whether the PNR detector can be used in the real system of quantum optics. This paper focuses on PNR detection technology based on InGaAs/InPAPD. Using the self-balanced peak signal suppression technique, the avalanche signal is collected with high fidelity, and the direct PNR detection based on InGaAs/InPAPD is realized by analyzing the distribution of the peak amplitude of the avalanche signal. On the basis of self-balancing peak signal suppression technique, a new scheme of double balance peak signal suppression technique is developed, which further compresses the peak signal and improves the signal-to-noise ratio of avalanche signal. Effectively improves the core performance of PNR detection. A 200 MHz multi-channel near-infrared single-photon detector prototype is developed, and the time-division multiplexed PNR detection based on InGaAs/InPAPD is realized. The POVM matrix of the detector is reconstructed experimentally by quantum detection chromatography. The experimental results of time-division multiplexing (TDM) PNR detection, the simulation results of theoretical model and the results calculated by using the reconstructed POVM matrix have a good agreement, which fully shows that QDT can accurately and reliably restore the TDM PNR detection process. The negative value of the Wigner function calculated by the reconstructed POVM at the origin indicates that this TDM PNR detection scheme based on the InGaAs/InPAPD multi-channel detector has the ability to detect the quantum states of photons and realizes the real quantum detection. The main innovations of this thesis are as follows: 1. Direct PNR detection based on InGaAs/InP APD is realized by using self-balanced peak signal suppression technique, and a new scheme of double-balanced peak signal suppression technique is proposed. The signal-to-noise ratio of avalanche signal is further improved to 11.2dB.2. A multi-channel 200 MHz near-infrared single-photon detector prototype has been developed. The highest detection efficiency of the four channels is higher than 25 and the dark count is less than 1 脳 10 ~ (-5) / pulse 路3 when the detection efficiency is 10. Time division multiplexing (TDM) PNR detection is realized by using multi-channel single-photon detector, and the POVM matrix of PNR detector is reconstructed by using QDT in experiments. The reduction degree of the output distribution calculated by using the reconstructed POVM matrix is as high as 99.9999. The negative value of the Wigner function corresponding to the reconstructed POVM matrix at the origin verifies the quantum properties of the PNR detector, which indicates that the PNR detector has the ability to detect photon quantum states.
【学位授予单位】：华东师范大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O431.2

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