太赫兹空气相干探测技术中锁相放大器参数的影响与优化  

Influence and optimization of parameters of lock⁃in amplifier in Terahertz air coherent detection technology

作　　者：龙江 王婧仪 杜海伟 LONG Jiang;WANG Jingyi;DU Haiwei(School of Testing and Optoelectronic Engineering,Nanchang Hangkong University,Nanchang 330063,China;Key Laboratory of Nondestructive Testing(Ministry of Education),Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学测试与光电工程学院,江西南昌330063 [2]南昌航空大学无损检测技术教育部重点实验室,江西南昌330063

出　　处：《现代电子技术》2023年第11期155-159,共5页Modern Electronics Technique

基　　金：国家自然科学基金项目(12064028);南昌航空大学无损检测技术教育部重点实验开放基金(EW202108218)。

摘　　要：锁相放大器在微弱信号测量中有非常重要的作用。在太赫兹空气相干探测技术中利用外置调制电场对激光在气体中四波混频作用产生的二次谐波进行调制,并以调制电场的频率作为锁相放大器的参考频率,能够完成对微弱的激光二次谐波的测量,使得二次谐波和太赫兹波电场成正比,从而将该探测技术转换成相干探测技术。采用Simulink对太赫兹空气相干探测技术中的锁相放大器参数的影响进行仿真,研究脉冲信号的宽度和锁相放大器的参数对探测结果的影响,并获得该测量过程所需的最优化参数。研究结果对太赫兹空气相干探测技术中锁相放大器的参数选取和设置有很好的理论参考价值。Lock⁃in amplifier plays an important rovle in the measurement of weak signals.In the Terahertz air coherence detection technology,the external modulated electric field is used to modulate the second harmonic generated by the laser in the four⁃wave mixing effect in the gas,and the frequency of the modulated electric field is taken as the reference frequency of the lock⁃in amplifier to complete the measurement of the weak laser second harmonic,so that the second harmonic is proportional to the Terahertz wave electric field.Thus,the detection technique is transformed into coherent detection technique.Simulink is used to simulate the influence of the parameters of in terahertz air coherence detection technology.The influence of the width of the pulse signal and the parameters of the lock⁃in amplifier on the detection result is investigated,and the optimal parameters required in the process of the measurement are obtained.The research results offer a good reference for selecting and setting parameters of the lock⁃in amplifier in Terahertz air coherence detection technology.

关 键 词：微弱信号测量 相干探测 锁相放大器 参数选取 参数优化 二次谐波调制 

分 类 号：TN911.7-34[电子电信—通信与信息系统] O434.3[电子电信—信息与通信工程]