单光子探测技术

近年来,以量子密钥分配为代表的各种量子信息技术应用获得了飞速发展,这些应用对单光子探测器的性能提出了非常苛刻的要求,以光电倍增管和雪崩光电二极管为代表的传统单光子探测器件已经无法满足需求。在此背景下,出现了以超导单光子探测器为代表的新型低温单光子探测器件,其性能比现有商用单光子探测器有了本质性的提升。本文综述了迄今为止各种类型的单光子探测器,并指出各自在量子信息技术应用中的优势和不足之处以及发展方向。     

单光子探测技术

近年来,以量子密钥分配为代表的各种量子信息技术应用获得了飞速发展,这些应用对单光子探测器的性能提出了非常苛刻的要求,以光电倍增管和雪崩光电二极管为代表的传统单光子探测器件已经无法满足需求。在此背景下,出现了以超导单光子探测器为代表的新型低温单光子探测器件,其性能比现有商用单光子探测器有了本质性的提升。本文综述了迄今为止各种类型的单光子探测器,并指出各自在量子信息技术应用中的优势和不足之处以及发展方向。     

单光子探测器APD无源抑制特性研究

为了选择高性能单光子探测器件，采用无源抑制方法对工作在盖革模式下的雪崩光电二极管（APD: avalanche photodiode）特性进行了测量。利用APD两端的电压在雪崩后趋于稳定的特性，获得了一种确定暗击穿电压的方法。特性测量实验结果表明：降低温度能加宽APD的最佳工作区域范围，并提高最佳增益值，从而使APD具有更高的灵敏度。通过对EG&;G系列APD和外延APD暗电流和信噪比特性进行比较，发现外延 APD具有良好的噪声性能和信噪比性能，适用于单光子探测。     

单光子超导探测器

利用超导铌及绝缘隧道阻挡层构成的器件可在200－500nm波长范围内以2．5kHz的速率探测单个光子，其本征光谱分辨率为45nm，量子效率可达50％。     

单光子探测器量子效率的绝对自身标定方法

提出一种单光子探测器量子效率的绝对自身标定方案，利用光参量下转换过程中产生的光子对在时间上的相关性，先将参量光束分为两路，然后引入相对延时，使同时产生的孪生光子先后进入单光子探测器，然后将探测器之后的电路分为三路，其中一路直接进入计数器得到探测器所探测到的光子的总计数率，另两路用电路方法引入和光路相当的相对延时，经符合电路后进入计数器，得到前后到达探测器的光子对之间的符合计数率.这样，从符合计数率与总光子计数率之比即可在不需要任何其他探测器或者参照标准的情况下获得探测器的量子效率.文中给出两种方案，分别适     

确定单光子计数系统中最佳甄别电压的实验研究

在光电倍增管相关理论的基础上从改变功率、积分时间、减光片、阴极电子加速电压等方面,通过实验利用Matlab软件对曲线进行拟合,通过该方法得到了光子计数率与功率、信噪比与功率、信噪比与积分时间之间的关系以及光电倍增管的相关特性.最后确定了单光子计数系统中最佳甄别电压的具体方法.     

超导转变边沿单光子探测器原理与研究进展

量子信息技术近十多年来的快速发展对单光子探测器的性能提出了更高的要求,高性能单光子探测器也因此受到了更多的关注.与传统的单光子探测器相比,超导转变边沿(TES)单光子探测器在探测效率、能量分辨、光子数分辨和暗计数等方面具有突出优势.目前,超导TES单光子探测器已经被成功地应用在量子光学实验和量子密钥分配系统中,未来在量子信息技术等研究领域具有更广泛的应用.本文从超导TES单光子探测器的工作原理、制备流程、测试系统、主要性能指标以及研究现状和进展等方面对该探测器技术进行简要综述.     

真空光电探测器件的发展动向及其应用

真空光电探测器件的发展动向及其应用陈举忠（南京电子器件研究所，２１００１６）［摘要］介绍光电倍增管、高灵敏度高分辨率视像管、ＥＢＣＣＤ／像增强器、条纹管类光电探测器的发展现状及其应用。关键词：光电探测器，光电倍增管，视像管，条纹管ＴＨＥＤＥＶＥＬＯＰ...     

用单光子偏振态的量子密码通信实验

根据海森堡测不准原理，使用量子密码可以使通信双方不需要事先准备相同的密码本即可绝对保密地通信，我们基于单光子偏振态的方案利用四个发光二极管作为光子源进行了传送量子公开密钥的原理性实验，得到的未经纠错的系统误码率为６％。     

Preliminary results for the design,fabrication,and performance of a backside-illuminated avalanche drift detector

The detection of low-level light is a key technology in various experimental scientific studies. As a photon detector, the silicon photomultiplier （SiPM） has gradually become an alternative to the photomultiplier tube （PMT） in many applications in high-energy physics, astroparticle physics, and medical imaging because of its high photon detection efficiency （PDE）, good resolution for single-photon detection, insensitivity to magnetic field, low operating voltage, compactness, and low cost. However, primarily because of the geometric fill factor, the PDE of most SiPMs is not very high; in particular, for those SiPMs with a high density of micro cells, the effective area is small, and the bandwidth of the light response is narrow. As a building block of the SiPM, the concept of the backside-illuminated avalanche drift detector （ADD） was first proposed by the Max Planck Institute of Germany eight years ago; the ADD is promising to have high PDE over the full energy range of optical photons, even ultraviolet light and X-ray light, and because the avalanche multiplication region is very small, the ADD is beneficial for the fabrication of large-area SiPMs. However, because of difficulties in design and fabrication, no significant progress had been made, and the concept had not yet been verified. In this paper, preliminary results in the design, fabrication, and performance of a backside-illuminated ADD are reported; the difficulties in and limitations to the backside-illuminated ADD are analyzed.     

Coalescence of two antiparallel photons into one photon on an electron (general case)

Feynman's method is used to calculate the differential and total probabilities of the process of coalescence of two photons into one photon on an electron when the momenta of the initial photons are antiparallel. Different kinematic variants of the effect are considered in the non-relativistic and ultrarelativistic regions of the energies of the initial photons.Translated from Izvestiya Uchebnykh Zavedenii, Fizika, No. 5, pp. 93–95, May, 1980.     

Splitting of a polarized photon by an unpolarized electron

The process of splitting of a polarized photon of a plane electromagnetic wave into two polarized photons by an unpolarized electron is examined. The degree of circular and linear polarization of the photon radiated is studied in detail.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 133–138, August, 1978.The authors are grateful to Professor V. G. Bagrov for discussing the research.     

Splitting of a photon into three by an electron

The process of splitting a photon into three by an electron is considered in this paper. A calculation is carried out in the lower order of perturbation theory, based on the exact solution of the problem concerning the motion of an electron in the field of a quantized plane electromagnetic wave. The photons of the wave are taken to be linearly polarized in both the initial and final states and the electron is unpolarized. The -component of the differential and total emission probability is calculated. Special cases of the differential and total probability for the polarized photon emitted are presented.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 12–15, February, 1979.In conclusion, the authors thank Professor V. G. Bagrov for attention to work.     

Current tensor with heavy photon for double hard photon emission by a longitudinally polarized electron

The electron current tensor for the scattering of a heavy photon on a longitudinally polarized electron with the emission of two hard real photons is considered. The contributions of collinear and semicollinear kinematics are computed. The result allows one to calculate the corresponding contribution to the second-order radiative correction to the deep inelastic scattering or electron-positron annihilation cross sections with next-to-leading-order accuracy. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 12, 845–850 (25 June 1999) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Time-resolved two photon photoemission electron microscopy

Femtosecond, time-resolved two photon photoemission has been used to map the dynamics of photo-excited electrons at a structured metal/semiconductor surface. A photoemission microscope was employed as a spatially resolving electron detector. This novel setup has the potential to visualize variations of hot electron lifetimes in the femtosecond regime on heterogeneous sample surfaces and nanostructures. Received: 22 October 2001 / Revised version: 10 January 2002 / Published online: 7 February 2002     

Nonlinear optics with less than one photon

We demonstrate suppression and enhancement of spontaneous parametric down-conversion via quantum interference with two weak fields from a local oscillator (LO). Effectively, pairs of LO photons up-convert with high efficiency for appropriate phase settings, exhibiting an effective nonlinearity enhanced by at least 10 orders of magnitude. This constitutes a two-photon switch and promises to be applicable to a wide variety of quantum nonlinear optical phenomena.     

Emission of a photon by an electron in a radiation-dominant universe

The process by which a photon is emitted by an electron in a radiation-dominant universe is considered, under the assumption that an arbitrary number of pairs are produced from a vaccum. In a flat space this process is forbidden by the laws of conservation. The dependence of the probability and the mean number of created particles on the energy of the initial electron is investigated. In the limiting cases (initial electron with high or low energies), approximate expressions are found for the probability that a photon is emitted by an electron as well as for the total probability of the process, including production of photons and pairs from a vacuum. Approximate expressions are obtained for the mean number of particles that are produced in the course of inelastic scattering of an electron in the early Universe. Biy State Pedagogical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 98–102, September, 1996.     

Emission of a photon by an electron in the radiation-dominated universe

We consider the process of photon emission by an electron in the radiation-dominated universe. We find a differential probability for the process and discuss various kinematic variants. We show that the total probability of the process is finite.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 29, No. 9, pp. 96–100, September, 1986.     

Inner-shell ionization of atoms by electron,positron and photon impacts

Plane wave Born approximation with Coulomb, relativistic and exchange corrections is employed to obtain L1-, L2- and L3-subshell ionization cross sections of several atoms due to electron and positron impacts for projectile energy varying from the threshold of ionization to 60 times the threshold energy. Photoionization cross sections for all the three L-subshells of the atoms are also calculated using the hydrogenic approximation for the atomic wave functions. For L3-subshell the present cross sections due to electron impact are in good agreement with a number of experimental data for different atoms over the entire energy range investigated. For L1- and L2-subshells the present calculations yield qualitative agreement with the experimental data. The agreement between the present results and the limited experimental data for positron impact is also satisfactory. The hydrogenic approximation for the L-subshell photoionization is found to be good at small photon energies but it underestimates the cross sections at large photon energies.