基于Tm∶YAG激光腔内泵浦的12.1 W,2129 nmHo∶YAP激光器  

12.1 W,2129 nm Ho∶YAP Laser Based on Tm∶YAG Laser Intra-Cavity Pumping

作　　者：李楠 黄海洲[2,3,5] 史斐 翁文[2,5] 李锦辉[2,5] 刘华刚 林文雄[2,5] Li Nan;Huang Haizhou;Shi Fei;Weng Wen;Li Jinhui;Liu Huagang;Lin Wenxiong(College of Chemistry and Materials Science,Fujian Normal University,Fuzhou 350007,Fujian,China;Key Laboratory of Optoelectronic Materials Chemistry and Physics,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,Fujian,China;Fujian Provincial Key Laboratory of Photonic Technology,Key Laboratory of Optoelectronic Science and Technology for Medicine of the Ministry of Education,College of Photonic and Electronic Engineering,Fujian Normal University,Fuzhou 350007,Fujian,China;Fujian College,University of Chinese Academy of Sciences,Fuzhou 350002,Fujian,China;Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China,Fuzhou 350108,Fujian,China)

机构地区：[1]福建师范大学化学与材料学院,福建福州350007 [2]中国科学院福建物质结构研究所光电材料化学与物理重点实验室,福建福州350002 [3]福建师范大学光电与信息工程学院医学光电科学与技术教育部重点实验室福建省光子技术重点实验室,福建福州350007 [4]中国科学院大学福建学院,福建福州350002 [5]中国福建光电信息科学与技术创新实验室,福建福州350108

出　　处：《中国激光》2024年第22期58-65,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(62275247,61905246);福建省光电信息科技创新实验室自主部署项目(2021ZZ101)。

摘　　要：提出了基于YAG/Tm∶YAG板条激光腔内泵浦的高效率室温Ho∶YAP激光器。采用c轴切割的Ho∶YAP激光晶体,获得了最高12.07 W的2129 nm Ho激光输出(激光电场E//b),斜率效率为32.2%,光-光转换效率为28.7%。同时,在平行于c轴的方向上,观察到Ho∶YAP晶体在激光波长处存在再吸收峰。采用a轴切割的Ho∶YAP晶体时,最高Ho激光功率下降到9.48 W,斜率效率为26.1%,光-光转换效率为23%,中心波长为2118.5 nm(E//c)。研究结果为利用常规半导体激光器直接泵浦的紧凑谐振腔获得高效率、线偏振室温Ho激光输出提供了有效的参考方案。Objective Ho-doped gain media, which feature absorption and emission transition between manifolds 5I8 and 5I7, have longer lasing wavelengths(2 μm) and larger emission cross-sections than Tm-doped gain media. Thus, Ho lasers are more advantageous in various applications such as mid-infrared nonlinear frequency generation, photo-electronic countermeasures, medical treatment, and laserrange identification. However, high power Ho lasers with high slope efficiencies(SEs) can be obtained by in-band pumping 1.9 μm Tm laser sources. Nonetheless, the required system is large and expensive, which renders it impractical and inaccessible in many applications. In this study, an efficient Ho∶YAP laser pumped with a composite Tm∶YAG slab laser intra-cavity is demonstrated. The results provide an effective scheme to directly use typical laser diodes(LDs) to achieve a compact, accessible, linearly-polarized 2.1 μm laser at room temperature.Methods A fiber-coupled 785 nm LD, with a core diameter of 400 μm and a numerical aperture(NA) of 0.22, is used as a pump source to pump the absorption peak of a Tm∶YAG crystal. Plano-convex lenses F1 and F2, which feature identical focal lengths of 40 mm, are utilized to collimate and focus the pump light into a spot with a diameter of 380 μm within the Tm∶YAG crystal.Additionally, a Tm∶YAG crystal with a cross-section measuring 1.5 mm×6.0 mm and a length of 17 mm is applied. As more severe thermal effects occur in the Tm-doped gain medium during intra-cavity pumping, the pump end of the Tm∶YAG crystal is diffusion boned with another 3 mm long YAG slice to alleviate the thermal effects. Two Ho∶YAP crystals measuring 3 mm×3 mm×7 mm are applied, which are cut along the crystallographic a-and c-axes, to compare the Ho laser performance. A 42-mm-long plano-concave resonator is developed for intra-cavity pumping. The beam quality is evaluated using a pyroelectric camera, and the laser wavelength is measured using a spectral analyzer.Results and Discussions Efficient Tm laser

关 键 词：2.1μm激光器 腔内泵浦 Tm∶YAG板条 Ho∶YAP Tm激光 

分 类 号：O436[机械工程—光学工程]