全固态单频Nd:YVO_(4)激光器强度噪声抑制的理论分析  

Theorotical Analysis of Intensity Noise Suppression in All-solid-state Single-frequency Nd:YVO_(4)Laser

作　　者：李瑾妮 刘婵 翟泽辉[1] 刘建丽 LI Jin-ni;LIU Chan;ZHAI Ze-hui;LIU Jian-li(School of Physics and Electronic Engineering,Shanxi University Taiyuan 030006,China)

机构地区：[1]山西大学物理电子工程学院,山西太原030006

出　　处：《量子光学学报》2023年第4期105-114,共10页Journal of Quantum Optics

基　　金：国家自然科学基金(11504217)。

摘　　要：低噪声的全固态单频Nd:YVO_(4)激光器在量子精密测量和引力波探测中有重要的应用。激光器的弛豫振荡是影响激光器噪声水平的主要因素,优化激光器的泵浦、输出耦合透射率和内腔损耗等参数,只能微小改善激光器的强度噪声,调整或改变激光器的弛豫振荡状态才是有效降噪方式。光电负反馈技术,通过对噪声传递函数的增益和相位的改变有效抑制了弛豫振荡;注入锁定技术,通过低噪声注入场的影响来改变弛豫振荡状态,从而有效抑制弛豫振荡噪声。利用光电负反馈和注入锁定两种技术相结合,在反馈光束分束ε=10%、反馈回路直流增益g=15 dB、相位超前φ=60°、注入锁定功率放大因子H=20时,可使声频区的激光器强度噪声降低5 dB、弛豫振荡峰值噪声降低39 dB。Low noise all-solid-state single-frequency Nd:YVO_(4)lasers are important for applications in quantum precision measurement,atomic frequency standard,non-classical state preparation and gravitational wave detection.The laser’s intensity noise has become a crucial parameter since it can directly affect measurement accuracy or experimental results.By altering laser parameters such as the intensity noise of the pump,intracavity losses,and the transmission of output coupler,the intensity noise of the all-solid-state single-frequency Nd:YVO_(4)laser is fully investigated.The intensity noise can only be slightly improved by optimizing these parameters.The main factor affecting noise level is relaxation oscillation,thus changing the state of relaxation oscillation is an efficient method for reducing the intensity noise.By altering the gain and phase of the noise transfer function,the photoelectronic negative feedback technique can effectively suppress the intensity noise.The intensity noise is reduced by about 5 dB in the audio frequency region and by about 36 dB at the relaxation oscillation frequency with the support of reflectivity of beam splitterε=10%,DC gain g=15 dB,the amount of phase advanceφ=60°and the pump noise VP=15 dB.By using a low noise injection field,the injection locking technology can modify the relaxation oscillation’s state and effectively suppress the noise in the relaxation oscillation frequency region.The maximum intensity noise is decreased by around 31 dB with the help of injection laser noise Vin=5 dB,injection locking power amplification ratio H=50 and the pump noise VP=15 dB.The photoelectric negative feedback technique may reduce noise in both the audio frequency region and the relaxation oscillation frequency region,the injection locking technique can only do so in the relaxation oscillation frequency region.The noise in the relaxation oscillation zone can be suppressed more strongly by combining the two techniques.The intensity noise of the all-solid-state single-frequency Nd:YVO_(

关 键 词：全固态单频Nd:YVO_(4)激光器 强度噪声 光电负反馈技术 注入锁定技术 

分 类 号：TN248.1[电子电信—物理电子学]