基于锁模激光不同时刻脉冲对间双光子干涉的介质色散测量  

Measurement of Dispersion Using Two-photon Interference between Pairs of Pulses from Mode-locked Laser at Different Time

作　　者：雷宇航 赵雯 崔亮 李小英[1,2] LEI Yu-hang;ZHAO Wen;CUI Liang;LI Xiao-ying(School of Precision Instruments and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China;Key Laboratory of Opto-Electronic Information Technology(Ministry of Education),Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]天津大学光电信息技术教育部重点实验室,天津300072

出　　处：《量子光学学报》2024年第3期1-9,共9页Journal of Quantum Optics

基　　金：国家自然科学基金(91836302)。

摘　　要：Hong-Ou-Mandel干涉指不可区分的两个光子分别从两个输入口入射进光学分束器后,倾向于从光学分束器同一输出口出射的现象,在量子信息领域具有广泛应用。作为一种双光子干涉现象,Hong-Ou-Mandel干涉可见度取决于两个入射光场的模式不可区分性,即两者在不同自由度下的模式匹配程度。对于独立脉冲光场的Hong-Ou-Mandel干涉,入射场时间模式的匹配程度是决定干涉图样的关键因素。由此,以锁模激光为光源,以不等臂Mach-Zehnder干涉仪为主要结构的双光子干涉装置可以通过测量干涉图样反映两臂光场的时间模式信息,例如线性啾和脉宽,从而实现对光学介质色散的测量。通常,Hong-Ou-Mandel干涉图样需要由两个探测器同步测量的符合计数描绘;本文基于锁模脉冲序列的相干性,提出了一种从单个探测器不同时刻的光子计数事件中统计符合计数,获得干涉图样的方案,该方案涉及两对脉冲间的双光子干涉。实验结果表明,新方案测得的干涉图样可以与实际的Hong-Ou-Mandel干涉图样互补,能用于色散测量等应用。该方法有助于实验装置的简化,对提高装置可靠性具有重要意义。Objective The Hong-Ou-Mandel interference refers to the phenomenon where two indistinguishable photons,injected from two input ports into an optical beam splitter,tend to emerge from the same output port of it.As a two-photon interference phenomenon,the visibility of the interference pattern hinges on the similarity of the incident fields,that is,the mode matching in different degrees of freedom.For Hong-Ou-Mandel interference of independent pulses,the temporal mode matching degree between the incident fields is a key factor of the interference pattern.Consequently,this effect can be used to measure the group delay dispersion of the transmission medium.Furthermore,the coherence of mode-locked pulse sequences,specifically within the context of Hong-Ou-Mandel interference between two coherent pulse trains,enables two-photon interference involving pairs of pulses arriving at the beam spliter at different times,thereby facilitating dispersion measurements through the interference of these temporallydistinct pairs.Method This paper delves into the two-photon interference occurring between pairs of coherent photons arriving at different times at a beam splitter within an unbalanced Mach-Zehnder interferometer.Starting from a single mode-locked laser,two pulse trains emerge after passing through a beam splitter,with one subsequently modulated by a phase modulator to ensure phase independence of each pulse pair at the second beam splitter for photon-counting.Traditionally,the Hong-Ou-Mandel interference relies on coincident detections from two single-photon detectors,each at a different output port of the beam splitter,within the same time window.This paper,however,examines the scenario where coincident eventspreviously limited to the same time frame across different detectors-can now arise from distinct time intervals and even a single detector.By collecting boolean sequences from the detectors over a defined period,we processed the coincidence rates after the measurements to reveal how the interference patterns evolve

关 键 词：Hong-Ou-Mandel干涉仪 相干态双光子干涉 符合计数 

分 类 号：O431[机械工程—光学工程]