超稳激光频率锁定系统中干涉效应抑制与锁频电路设计  

Interference Suppression and Frequency-Locking Circuit Design in Ultra-Stable Laser Systems

作　　者：肖锐 晏北飞 蔡桢荻 方鹏程 徐晏琪 王艳 孙焕尧 陈群峰 Xiao Rui;Yan Beifei;Cai Zhendi;Fang Pengcheng;Xu Yanqi;Wang Yan;Sun Huanyao;Chen Qunfeng(Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430071,Hubei,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院精密测量科学与技术创新研究院波谱与原子分子物理国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049

出　　处：《中国激光》2024年第7期241-249,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划(2020YFA0309801);中国科学院稳定支持基础研究领域青年团队计划(YSBR-055)。

摘　　要：超稳激光是精密测量领域的关键工具,其频率稳定度很大程度上取决于频率锁定稳定度。笔者理论研究了干涉效应对锁频误差信号的影响,并通过实验研究了降低干涉效应的方法,以提高激光的频率锁定稳定度。经过优化后,锁频系统的锁定稳定度相对于参考腔线宽达到了9×10^(-7)。在参考腔线宽为21 kHz(精细度为7.5万)的情况下,将1.5μm激光的频率稳定度锁定到4.0×10^(-16)水平,接近10 cm参考腔的热噪声极限。本文所提降低干涉效应的方法是研制稳定度高达10^(-17)水平的超稳激光器的重要参考。Objective Ultra-stable lasers,characterized by high-frequency stability and extremely narrow linewidths,serve as vital tools in precision measurement and physics research.They find extensive applications in fields such as atomic clocks,gravitational wave detection,and quantum communication.With improvements in experimental precision,the demand for lasers with narrower linewidths and higher frequency stability has increased.Therefore,enhancing the frequency stability of ultra-stable lasers has become a significant area of research.Currently,the Pound‒Drever‒Hall(PDH)frequency stabilization technique is widely used for generating ultra-stable lasers.By employing this technique,the laser frequency is locked to a high-precision Fabry‒Perot(FP)cavity to reduce the laser linewidth and improve frequency stability.If the feedback system has a sufficiently high signal-to-noise ratio(SNR),an appropriate loop bandwidth,and gain,it can fully suppress the free-running frequency noise and drift of the laser.Ultimately,the frequency stability primarily depends on the performance of the ultra-stable cavity(reference cavity),which serves as the frequency reference,and the servo system that controls the laser frequency.Thus,enhancing the stability of the reference cavity and optimizing the performance of the frequency-locking system are critical for improving the frequency stability of ultra-stable lasers.Methods This study theoretically investigates the influence of interference effects on PDH locking error signals and identifies optimization directions for the optical path.In experiments,a reflection mirror was initially used instead of the reference cavity to prevent data distortion caused by laser frequency drifts when the laser operates freely and scans through the resonances of the reference cavity.Subsequently,an Agilent 34401A digital multimeter was employed to measure the voltage values of the locking error signals under different optical path conditions.The stabilities of the locking error were calculated and compa

关 键 词：激光器 激光稳定 Pound‒Drever‒Hall稳频 干涉效应 超稳腔 超稳激光 

分 类 号：TN248[电子电信—物理电子学]