端面抽运Nd:YAG/Cr^(4+):YAG/KTA被动调Q级联拉曼激光器  

End-pumped Nd:YAG/Cr^(4+):YAG/KTA passive Q-switched cascade Raman laser

作　　者：齐子钦 毛文杰 王鸿雁 朱小龙 裘馨楠 陆欢洽 朱海永[1] Qi Ziqin;Mao Wenjie;Wang Hongyan;Zhu Xiaolong;Qiu Xinnan;Lu Huanqia;Zhu Haiyong(Wenzhou Key Laboratory of Micro-Nano Optoelectronic Devices,College of Electrical and Electronic Engineering,Wenzhou University,Wenzhou 325035,China;Crystech Inc.,Qingdao 266100,China)

机构地区：[1]温州大学电气与电子工程学院、温州市微纳光电器件重点实验室,浙江温州325035 [2]青岛海泰光电技术有限公司,山东青岛266100

出　　处：《红外与激光工程》2023年第10期49-54,共6页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(62275200);温州市基础性科研项目(G20220014);浙江省新苗人才计划课题项目。

摘　　要：报道了基于KTA晶体671 cm^(−1)和234 cm^(−1)频移的LD端面抽运被动调Q级联拉曼激光器。采用Nd:YAG/Cr^(4+):YAG复合晶体产生被动调Q的脉冲基频激光来驱动KTA晶体,研究了不同入射抽运功率下级联拉曼激光的输出功率、光谱和脉冲特性。随着抽运功率的增加,输出激光波长从以671 cm^(−1)和234 cm^(−1)频移级联拉曼的1178 nm单波长过渡到与1212 nm同时输出的双波长。在10.05 W的入射抽运功率下,获得了280 mW平均输出功率,6.2%转化效率的双波长激光。对应的脉冲宽度和重复频率分别为1.2 ns和10.3 kHz,单脉冲能量和峰值功率分别为27.2μJ和22.7 kW。结果表明:基于KTA两个相当增益强度的频移,结合腔镜镀膜控制可以获得丰富的斯托克斯激光波长。Objective KTA crystal as Raman gain medium has attracted increasing attention.Its larger Raman gain and smaller Raman shift make it more advantageous for cascade Raman conversion to obtain new wavelength Stokes laser of 1178 nm and 1212 nm.The frequency doubling of both two Stokes laser could realize yellow and orange emissions which have important applications in remote sensing,laser medicine and so on.In particular,1212 nm laser has an absorption affinity for lipid-rich tissues and can be used to stimulate adipose cells and mesymal fine tissue in subcutaneous tissues,which is an ideal source for laser assisted skin healing and prevention of excessive scar formation.In view of the important applications of 1178 nm and 1212 nm laser,KTA cascade Raman operation driven by passive Q-switched laser for these two wavelengths generation was further investigated.Methods The laser system for KTA cascade Raman operation is shown(Fig.1).Nd:YAG/Cr^(4+):YAG composite was used for passive Q-switched laser generation.Cr^(4+):YAG crystal,with an initial transmittance of about 85%,was used as saturable absorber crystal and diffusion bonded to Nd:YAG crystal to make the laser system more compact and easy to dissipate heat.An x-axis cut KTA crystal with 25 mm in length was used as the Raman crystal.The plano-concave cavity with the total cavity length of about 50 mm guarantees the effective oscillation of the fundamental laser and Raman laser.The specific coating parameters are shown(Fig.2).The transmittance of Stokes wavelengths based on the Raman shift of 234 cm^(−1)and 671 cm^(−1)is also given(Fig.2).Results and Discussions With the increase of Raman laser output power,we found the Stokes laser was accompanied by a small amount of yellow laser output,and the corresponding yellow light spectrum was shown(Fig.3).Under an incident pumping power of 10.05 W,an average output power of 280 mW was obtained,and the conversion efficiency is 2.8%.The output power and laser wavelength are shown(Fig.4-5).From the threshold to 8 W incide

关 键 词：拉曼激光 KTA晶体 被动调Q YAG晶体 

分 类 号：O436[机械工程—光学工程]