Based on the fact that a two-mode squeezed number state is a two-variable Hermite polynomial excitation of the two-mode squeezed vacuum state, the result of one-mode l-photon measurement for the two-mode squeezed numb...Based on the fact that a two-mode squeezed number state is a two-variable Hermite polynomial excitation of the two-mode squeezed vacuum state, the result of one-mode l-photon measurement for the two-mode squeezed number state S2｜m, n） is discussed. It is found that a remaining field-mode simultaneously collapses into a number state ｜n - m＋l｜ with the coefficient being a Jacobi polynomial of n, m and l, which manifestly exhibits the entanglement between the two modes, i.e. it depends on the number-difference between the two modes. The second mode collapses into an excited coherent state when the first mode is measured as a coherent state.展开更多
基于超导原理的超导纳米线单光子探测器(superconducting nanowire single photon detector,SNSPD)以其在高量子效率、高计数率、低暗计数和低时间抖动等方面的优势引起广泛的研究。综述了SNSPD的物理模型和研究进展。首先从第一次在实...基于超导原理的超导纳米线单光子探测器(superconducting nanowire single photon detector,SNSPD)以其在高量子效率、高计数率、低暗计数和低时间抖动等方面的优势引起广泛的研究。综述了SNSPD的物理模型和研究进展。首先从第一次在实验上发现超导铅薄膜的电热效应出发讲述了SNSPD的起源。然后从SNSPD进行单光子探测的物理过程出发详细分析了SNSPD的单光子探测机制,并分别根据电热模型和唯象模型对探测机制进行了详细的物理解释。紧接着,详细阐述了量子效率分析模型,指出SNSPD的系统量子效率由本征量子效率、耦合效率和光吸收效率三部分组成。最后,从如何提高入射光子与SNSPD的耦合效率、如何提高光子吸收效率、如何提高SNSPD本征量子效率、研究基于新型材料的SNSPD、如何实现光子数分辨和对光子偏振态不敏感的SNSPD、以及研究SNSPD的噪声机制以减小暗计数和时间抖动等方面详细列举了目前各小组研究SNSPD所取得的最新进展。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 10774108)
文摘Based on the fact that a two-mode squeezed number state is a two-variable Hermite polynomial excitation of the two-mode squeezed vacuum state, the result of one-mode l-photon measurement for the two-mode squeezed number state S2｜m, n） is discussed. It is found that a remaining field-mode simultaneously collapses into a number state ｜n - m＋l｜ with the coefficient being a Jacobi polynomial of n, m and l, which manifestly exhibits the entanglement between the two modes, i.e. it depends on the number-difference between the two modes. The second mode collapses into an excited coherent state when the first mode is measured as a coherent state.
文摘基于超导原理的超导纳米线单光子探测器(superconducting nanowire single photon detector,SNSPD)以其在高量子效率、高计数率、低暗计数和低时间抖动等方面的优势引起广泛的研究。综述了SNSPD的物理模型和研究进展。首先从第一次在实验上发现超导铅薄膜的电热效应出发讲述了SNSPD的起源。然后从SNSPD进行单光子探测的物理过程出发详细分析了SNSPD的单光子探测机制,并分别根据电热模型和唯象模型对探测机制进行了详细的物理解释。紧接着,详细阐述了量子效率分析模型,指出SNSPD的系统量子效率由本征量子效率、耦合效率和光吸收效率三部分组成。最后,从如何提高入射光子与SNSPD的耦合效率、如何提高光子吸收效率、如何提高SNSPD本征量子效率、研究基于新型材料的SNSPD、如何实现光子数分辨和对光子偏振态不敏感的SNSPD、以及研究SNSPD的噪声机制以减小暗计数和时间抖动等方面详细列举了目前各小组研究SNSPD所取得的最新进展。
