红外波段偏振纠缠光源的制备与性能研究  

Preparation and Performance Study of Polarization Entangled Light Sources in Near Infrared Bands

作　　者：吴杰 赵春柳 王海龙 张雄 石岩 陈君 龚波 占春连 金尚忠 WU Jie;ZHAO Chun-liu;WANG Hai-long;ZHANG Xiong;SHI Yan;CHEN Jun;GONG Bo;ZHAN Chun-lian;JIN Shang-zhong(College of Optical and Electronic Technology,China Jiliang University,Hangzhou 310018,China)

机构地区：[1]中国计量大学光学与电子科技学院,浙江杭州310018

出　　处：《量子光学学报》2024年第3期27-36,共10页Journal of Quantum Optics

基　　金：浙江省自然科学基金(LQ23A050006,LY22A040007,LQ23A050005)。

摘　　要：利用二阶非线性效应的自发参量下转换技术搭建偏振纠缠光源是目前实验中制备偏振纠缠光子对常用的方法之一,产生的偏振纠缠光子对分别被称为信号光子和闲置光子,它们具有特定的空间和频率关联性,使得量子密码学和量子通信等新技术的出现成为可能。本文理论分析了在周期极化磷酸氧钛钾晶体中进行准相位匹配参量下转换过程时,晶体的极化周期与温度对下转换光的波长的影响,并实验搭建了一套基于I类准相位匹配周期极化磷酸氧钛钾晶体参量下转换过程制备的近红外波段偏振纠缠光源,对实验中的光学路径以及数据采集方案进行了详细而系统的描述,并对偏振纠缠光源制备过程中的核心问题之一,即光源产生的偏振纠缠光子对的纠缠品质如何进行了讨论研究。实验结果表明,本实验所搭建的近红外波段偏振纠缠光源在偏振测量基分别为|H>|V>和|+>|->时,偏振纠缠光子对的干涉可见度可分别达到96.19%和95.28%,Bell不等式违背超过9个标准差,可以用作进一步的量子实验研究光源。Objective Using spontaneous parametric down-conversion based on second-order nonlinear effects to construct a polarized entangled photon source is one of the commonly employed methods in experimental setups nowadays.The produced entangled photon pairs,referred to as signal and idler photons,possess specific spatial and frequency correlations,which enable the development of novel technologies such as quantum cryptography and quantum communication.This paper theoretically analyzes the influence of the crystal's polarization period and temperature on the wavelength of down-converted light during quasiphase matching parametric down-conversion in periodically poled potassium titanyl phosphate crystals.Additionally,an experimental setup is constructed based on Type II quasi-phase matching in periodically poled potassium titanyl phosphate crystals to prepare a near-infrared polarized entangled photon source.Detailed and systematic descriptions of the optical paths and data acquisition methods in the experiment are provided.Furthermore,one of the key issues in the preparation of the polarized entangled photon pairs,namely,the quality of entanglement of the produced photon pairs,is discussed.The experimental results demonstrate that the near-infrared polarized entangled photon source built in this experiment achieves interference visibilities of 96.19%and 95.28%respectively for polarization measurement bases|H>/|V>and|+>/|->,with Bell inequality violations exceeding 9 standard deviations.This source can serve as a basis for further quantum experimental research.Method This paper first analyzes the factors influencing the generation of polarization-entangled photon pairs via parametric downconversion in PPKTP crystals using quasi-phase matching techniques.It clarifies the effects of crystal polarization period and temperature on the wavelength of the down-converted light,and based on this analysis,determines the polarization period and experimental temperature required for the PPKTP crystal.Subsequently,by combining the Sa

关 键 词：量子光学 纠缠光源:偏振关联曲线 Bell不等式违背 

分 类 号：O431.2[机械工程—光学工程]