基于外腔倍频的双色高重频飞秒激光产生  

Generation of dual-color high repetition rate femtosecond pulses with an external frequency-doubled cavity

作　　者：安岳松 李娟 项晓[1,2,3] 刘鹏[1,2,3] 董瑞芳 AN Yue-song;LI Juan;XIANG Xiao;LIU Peng;DONG Rui-fang(National Time Service Center,Chinese Academy of Sciences,Xi’an 710600,China;Key Laboratory of Time and Frequency Primary Standards,Chinese Academy of Sciences,Xi’an 710600,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 101048,China)

机构地区：[1]中国科学院国家授时中心,西安710600 [2]中国科学院时间频率基准重点实验室,西安710600 [3]中国科学院大学天文与空间科学学院,北京101048

出　　处：《时间频率学报》2021年第2期77-84,共8页Journal of Time and Frequency

基　　金：国家自然科学基金资助项目(61875205,61801458,91836301,12033007);中国科学院前沿科学重点研究资助项目(QYZDB-SSWSLH007);中国科学院“西部之光”人才培养计划“西部青年学者”B类资助项目(XAB2019B15,XAB2019B17);广东省重点研发资助项目(2018B030325001);中国科学院重点资助项目(ZDRW-KT-2019-1-0103);中国科学院战略性先导科技专项C类资助项目(XDC07020200)。

摘　　要：利用谐振腔的模式滤波及共振增强特性,进行了基于外腔倍频的双色高重频飞秒激光产生的实验研究。首先从理论上简单介绍了利用大自由光谱区的谐振腔实现飞秒脉冲重频变换的原理,并通过理论研究表明:腔内功率放大倍数会随着重频的增大而减小,进而限制倍频效率的增加。在实验上采用自由光谱区为300 MHz的六镜环形腔及1 mm厚的BIBO倍频晶体,输入重复频率为75 MHz的飞秒脉冲,实现了中心波长815 nm的基频和407.5 nm的倍频飞秒脉冲输出,其重频均为300 MHz,且重频信号的边模抑制比分别达到30 dB和20 dB。本文还进一步对实验产生的双色高重频飞秒激光的倍频效率、共振光谱、光束质量等特性进行了测量分析,为后续开展高重频量子光频梳实验研究奠定了基础。Utilizing the mode filtering and power enhancement characteristics of the optical cavity,a scheme for generating dual-color,high repetition rate femtosecond laser based on an external frequency-doubled cavity was proposed.Firstly,the feasibility of this method was analyzed theoretically,showing that the mode filtering can be realized by using an optical cavity with large free spectrum range(FSR),thus increasing the repetition rate of the laser pulse;at the same time,the power enhancement factor in the cavity would decrease with the increasing of the repetition rate,leading to a limited frequency doubling efficiency.A six-mirror ring cavity with a FSR of 300 MHz along with a piece of 1 mm-thick BIBO crystal was used in our experiment.As the femtosecond pulse with a repetition rate of 75 MHz was injected into the cavity,the fundamental frequency and its second harmonic were generated and then separated in space.The side-mode suppression ratios of 300 MHz repetition rate signal of the fundamental frequency(815 nm)and its second harmonic(407.5 nm)reaches 30 dB and 20 dB,respectively.Furthermore,the frequency doubling efficiency,resonance spectrum and beam profile were measured and analyzed,which will lay the foundation for high repetition rate quantum optical frequency comb generation.

关 键 词：飞秒激光 光学谐振腔 二次谐波产生 高重频 

分 类 号：TN248[电子电信—物理电子学]