高效率三倍频产生355nm皮秒激光的实验研究  

Efficient third harmonic generation of 355 nm picosecond laser pulse

作　　者：程梦尧 王兆华[2] 何会军[2] 王羡之 朱江峰 魏志义[2] Cheng Meng-Yao;Wang Zhao-Hua;He Hui-Jun;Wang Xian-Zhi;Zhu Jiang-Feng;Wei Zhi-Yi(School of Physics and Optoelectronic Engineering,Xidian University,Xi’an 710071,China;Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]西安电子科技大学物理与光电工程学院,西安710071 [2]中国科学院物理研究所,北京100190

出　　处：《物理学报》2019年第12期116-122,共7页Acta Physica Sinica

基　　金：中国科学院战略性先导科技专项(批准号:XDB16030200)、中国科学院前沿科学重点研究计划(批准号:KJZD-EW-L11-03)资助的课题;国家自然科学基金(批准号:11774410,61575217);国家重点研发计划(批准号:2017YFC0110301)~~

摘　　要：具有高重复频率、高平均功率的皮秒放大激光在科学研究和工业生产中有着重要的应用,尤其是在脆性材料的加工领域,绿光或紫外皮秒激光具有独特的优势.基于我们研制的平均功率23.2 W、重复频率500 kHz、脉冲宽度13.4 ps的Nd:YVO4激光器,开展了LBO晶体高效率二倍频与三倍频的研究.通过优化相位匹配和晶体内激光的走离,分别得到了平均功率12.7 W的532 nm二倍频激光和9.25 W的355 nm三倍频激光,相应的光光转换效率分别为54.7%和39.8%.激光器具有结构简单、平均功率高、转换效率高等特点,可以广泛地用于科学研究和工业生产中.Picosecond laser with high-repetition-rate and high pulse energy is widely favorite in many scientific and industrial applications. Some nonlinear crystals can be used to efficiently convert a near-infrared laser into a green laser or an ultraviolet laser which has a higher photon energy and a smaller focal area. Especially for high-quality and high-speed transparent hard material fabrication, green or ultraviolet picosecond laser has been found to possess unique advantages. In this paper, the experiments on high-efficiency second-harmonicgeneration(SHG) and third-harmonic-generation(THG) by using a home-made all-solid-state picosecond laser amplifier and an LBO crystal are reported.The picosecond laser amplifier consists of a seed source, a regenerative amplifier and a two-stage single-pass amplifier. The seed source is a commercial all-solid-state picosecond oscillator with a pulse duration of 8.3 ps and a repetition rate of 68 MHz. The repetition rate is reduced from 68 MHz to 500 kHz by an electro-optic Pockels cell(PC), and the period doubling bifurcation is minimized by reducing the duration of high voltage in PC. Both the regenerative amplifier and the two-stage single-pass amplifier are pumped by three 30-W continuous-wave fiber-coupled laser diodes. After the regenerative amplifier, the seed laser is amplified to 4.86 W with a repetition rate of 500 kHz at 1064 nm. Then the laser power is increased to 23.2 W by a two-stage single-pass amplifier, and the M2 value of the amplified laser in the X direction and in the Y direction are 1.330 and 1.235, respectively. The final pulse duration is 13.4 ps, which is slightly stretched in the amplification chain compared with the seed pulse duration(8.3 ps).For high-efficiency SHG and THG from near-infrared to green and ultraviolet, we carefully study the optical characteristics of some nonlinear crystals, such as LBO, BBO, BIBO, CLBO, etc., and we find that the LBO crystal, which has a high damage threshold, small walk-off and high nonlinear coefficient, is the bes

关 键 词：非线性光学 频率变换 二极管抽运激光器 放大器 

分 类 号：TN248[电子电信—物理电子学]