高功率高重复频率多波长飞秒激光系统的研究  

Study on the high-power,high-repetition-rate and multi-wavelength femtosecond laser system

作　　者：刘华刚[1] 胡明列[1] 刘博文[1] 宋有建[1] 柴路[1] 王清月[1] 

机构地区：[1]天津大学精密仪器与光电子工程学院光电信息技术科学教育部重点实验室,天津300072

出　　处：《物理学报》2010年第6期3979-3985,共7页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2010CB327604;2006CB806002);国家高技术研究发展计划(批准号:2007AA03Z447);国家自然科学基金(批准号:60978022;60838004);高等学校博士学科点专项科研基金(批准号:20070056083;20070056073);教育部科学技术研究计划重点项目(批准号:108032);全国优秀博士学位论文作者专项基金(批准号:2007B34);教育部新世纪优秀人才支持计划(批准号:NCET-07-0597)资助的课题~~

摘　　要：以大模场面积光子晶体光纤飞秒激光系统为基频光源,利用非线性频率上转换的方法,获得了高功率高重复频率多波长的飞秒激光脉冲.理论分析并实验验证了聚焦透镜的焦距对倍频光横向模场分布的影响,透镜焦距越长,模场质量越好.在基频光平均功率为21.8W,脉冲宽度为110fs,重复频率为50MHz的条件下,经过二倍频、三倍频和四倍频获得波长分别为520,347和261nm的飞秒激光,其平均功率分别达10.5,4.7和2.14W.二倍频和三倍频的转换效率分别为48.2%和21.6%,二倍频到四倍频的转换效率为20.4%.采用互相关法测量得到261nm紫外激光的脉冲宽度为408fs.High-power and high-repetition-rate multi-wavelength femtosecond pulses are obtained by the nonlinear frequency up-conversion of large mode area photonic crystal fiber femtosecond system. Effects of focal length on the transverse mode of second harmonic are theoretically analyzed and experimentally demonstrated,showing that the longer the focal length,the better the mode quality. Under the condition of fundamental average power of 21. 8 W,pulse duration of 110 fs and repetition rate of 50 MHz,generation of the second,third and fourth harmonics are achieved at the wavelengths of 520, 347,and 261 nm,with the maximum average power of 10. 5,4. 7,and 2. 14 W,respectively. The conversion efficiencies of frequency doubling and frequency tripling are 48. 2% and 21. 6% ,and the conversion efficiency of frequency quadrupling from the second harmonic is 20. 4% . Pulse duration of the fourth harmonic pulse is 408 fs,as measured by the cross-correlation technique.

关 键 词：超快光学 紫外飞秒激光 频率上转换 光子晶体光纤激光器 

分 类 号：TN249[电子电信—物理电子学]