1064 nm高功率明亮压缩态光场实验制备中的热透镜效应  

Thermal Lens Effect in Experimental Preparation of 1064 nm High-Power Bright Squeezed State

作　　者：郭锐 杨文海 郭咏[1] 姚慧 李丽丽 Guo Rui;Yang Wenhai;Guo Yong;Yao Hui;Li Lili(Department of Physics,Shanxi Agricultural University,Taigu 030801,Shanxi,China;China Academy of Space Technology(Xi'an),Xi'an 710000,Shaanxi,China)

机构地区：[1]山西农业大学物理系,山西太谷030801 [2]中国空间技术研究院西安分院,陕西西安710000

出　　处：《光学学报》2023年第21期309-315,共7页Acta Optica Sinica

基　　金：国家自然科学基金(62001374)。

摘　　要：本文通过理论和实验分析了1064 nm高功率明亮压缩态光场实验制备过程中,高功率种子光和泵浦光注入光学参量放大器引起的热透镜效应和模式失配。首先根据热透镜理论模型,定量分析了高功率种子光和泵浦光注入光学参量放大器时,周期极化磷酸氧钛钾晶体内部热透镜的等效焦距。然后根据高斯光束与光学谐振腔的模式匹配理论模型,理论分析了高功率种子光和泵浦光与光学参量放大器的模式失配量。最后在高功率明亮压缩态光场正常输出的工作状态下,重新优化种子光和泵浦光与光学参量放大器的模式匹配效率,在种子光功率为500 mW、泵浦光功率为145 mW的条件下,在分析频率3 MHz处,直接测得光功率为200μW、压缩度为-10.8 dB±0.2 dB的明亮压缩态光场。上述实验结果与有关文献测得的压缩度仅相差0.1 dB,表明在本文实验系统中,高功率种子光和泵浦光引起的热透镜效应对光学参量放大器输出明亮压缩态光场的压缩度基本没有影响。Objective As an important quantum resource,the squeezed state can not only be employed for quantum teleportation in quantum information technology but also can be adopted to improve the detection sensitivity of laser interferometer in quantum precision measurement.In the above applications,the quantum state fidelity and interferometer sensitivity are directly determined by the noise level of the squeezed state.Therefore,previous research focuses on improving the squeezing degree of squeezed state.However,with the deepening research,the optical power of the squeezed state is another factor limiting its application,and thus it is important to improve the optical power of the squeezed state.Methods The experimental preparation system is built as shown in Fig.1.The most important part of the experimental system is the optical parametric amplifier(OPA),which generates the high-power bright squeezed state.The OPA is a semi-monolithic standing cavity composed of periodically poled KTiOPO4(PPKTP)crystal and concave cavity mirror.Then the balanced homodyne detection device can divide the high-power bright squeezed state and the local oscillator into two parts with equal power,and inject the balanced homodyne detector respectively after interference.The squeezing degree is measured by scanning the relative phase of the high-power bright squeezed state and the local oscillator.The thermal lens effect of PPKTP crystal exerts a very adverse effect on the parametric conversion.The method of simultaneously injecting high-power seed light and pump light into OPA is adopted especially in the experimental system of preparing high-power bright squeezed state.This method will increase the nonlinear absorption of high-power seed light and pump light,resulting in thermal deposition and then a thermal lens effect in the PPKTP crystal.Finally,the mode matching efficiency of the seed light and pump light with OPA is decreased.To improve the mode matching efficiency of seed light and pump light with OPA and enhance the squeezing degree,we

关 键 词：量子光学 明亮压缩态 高功率 热透镜效应 

分 类 号：O436[机械工程—光学工程]