高效率连续波Nd∶YVO_(4)/KGW内腔拉曼激光器  

Efficient Continuous-Wave Nd∶YVO_(4)/KGW Intra-cavity Raman laser

作　　者：盛泉[1,2] 耿婧旎 李锦辉 付士杰[1,2] 史伟[1,2] 姚建铨[1,2] Sheng Quan;Geng Jingni;Li Jinhui;Fu Shijie;Shi Wei;Yao Jianquan(School of Precision Instrument and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China;Key Laboratory of Optoelectronics Information Technology,Ministry of Education,Tianjin University,Tianjin 300072,China;Chengxian College,Southeast University,Nanjing 210088,Jiangsu,China)

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]天津大学光电信息技术教育部重点实验室,天津300072 [3]东南大学成贤学院,江苏南京210088

出　　处：《中国激光》2024年第5期19-23,共5页Chinese Journal of Lasers

基　　金：国家自然科学基金(61975146,62105240,62075159)。

摘　　要：报道了基于Nd∶YVO_(4)激光晶体和钨酸钆钾(KGW)拉曼晶体的端面泵浦连续波内腔拉曼激光器,实验研究了基频激光偏振方向对KGW拉曼激光器输出功率、光谱和模式特性的影响。当基频光偏振方向平行于KGW晶体的Nm轴时,901 cm^(-1)拉曼频移增益较高,在36.6 W半导体激光泵浦功率下获得了6.63 W的1177.3 nm连续波斯托克斯光输出,光光效率和斜效率分别为18.1%和24.7%;而当基频光沿KGW晶体Ng轴偏振时,由于768 cm^(-1)和901 cm^(-1)两条拉曼谱线的竞争以及对应89 cm^(-1)小波数拉曼峰的级联拉曼斯托克斯光起振,拉曼激光器的光谱和功率特性均发生劣化。在实验中还观察到KGW像散的热透镜效应对激光模式产生的影响。Objective Stimulated Raman scattering(SRS)in the crystalline Raman gain media is a well-established technique for extending the spectral coverage of lasers.However,as a third-order nonlinear process,the SRS suffers a relatively low nonlinear gain and consequently has a high threshold,specifically when operating in a continuous-wave(CW)scheme.The intra-cavity pump scheme,in which the Raman crystal is located within the fundamental laser cavity,is an effective alternative to achieve efficient CW Raman output with moderate primary pump power because the high circulating fundamental laser power in the cavity generates sufficient Raman gain.To date,the highest CW Stokes output power of end-pumped intra-cavity Raman lasers has been realized with the self-Raman scheme,in which the processes of lasing and SRS take place in one crystal to minimize insertion losses.However,intra-cavity Raman lasers with separate lasers and Raman gain media have the advantages of a more flexible output wavelength and distributed thermal load,which are helpful for power scaling.This study presents an efficient CW Nd∶YVO_(4)/KGW intra-cavity Raman laser.The output power of the CW Stokes wave at 1177 nm reaches 6.63 W under an incident laser diode(LD)pump power of 36.6 W,with the corresponding optical efficiency being 18.1%.Methods The experimental setup of the CW intra-cavity Raman laser is shown in Fig.1.A 15 mm long a-cut Nd∶YVO_(4)crystal and a 20 mm long N_(p)-cut KGW crystal serve as the fundamental laser and Raman gain media,respectively.The LD pump wavelength is 878.6 nm,and the pump beam radius at the laser crystal is 280μm.The Nd∶YVO_(4)crystal has a low doping atomic fraction of 0.2%to alleviate the thermal effect.The 1064 nm fundamental laser cavity is defined by a flat highly reflective(HR)mirror(M1)and a curved HR mirror(M2)with a radius of curvature of 100 mm.The M2 also has a transmissivity of 0.4%at a Stokes wavelength of 1177 nm.A flat dichroic mirror(M3)with HR coating at 1.15-1.18μm and highly transmissive at 1064 n

关 键 词：激光器 受激拉曼散射 连续波拉曼激光器 内腔拉曼激光器 钨酸钆钾晶体 

分 类 号：TN248.1[电子电信—物理电子学]