不同切割方向Ho...YAP晶体激光输出特性的实验研究  

Experimental Investigation of Laser Output Characteristics of Ho…YAP Crystal in Different Cutting Directions

作　　者：赵开祺 刘晶[2,3] 余婷[2,3] 孟佳 司继良[4] 施翔春[2,3] 叶锡生[2,3] 曹清[1] Zhao Kaiqi;Liu Jing;Yu Ting;Meng Jia;Si Jiliang;Shi Xiangchun;Ye Xisheng;Cao Qing(College of Sciences,Shanghai University,Shanghai 200444,China;Laboratory of High Power Fiber Laser Technology,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Key Laboratory of Materials for High Power Laser,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]上海大学理学院,上海200444 [2]中国科学院上海光学精密机械研究所高功率光纤激光技术实验室,上海201800 [3]中国科学院上海光学精密机械研究所上海市全固态激光器与应用技术重点实验室,上海201800 [4]中国科学院上海光学精密机械研究所强激光材料重点实验室,上海201800

出　　处：《中国激光》2020年第4期175-181,共7页Chinese Journal of Lasers

基　　金：预研基金(6140A24010403)。

摘　　要：不同切割方向的Ho…YAP晶体的激光输出特性存在差别。针对掺杂浓度为0.5%(原子数分数)的Ho…YAP晶体开展a、b、c三种切割方向的激光输出特性实验研究。采用最大输出功率为44.3W的1915nm掺铥光纤激光器端面泵浦Ho…YAP晶体,在三种切割方向上均获得了大于20 W的连续激光输出,其中b向切割晶体输出激光的中心波长近2118nm,最大功率为23.6W,斜率效率为61.98%,a向切割晶体与b向切割晶体的输出结果相近,c向切割晶体在达到最大输出功率时的中心波长为2129nm;当采用腔内声光调Q获得脉冲输出时,a、c向切割晶体出现了中心波长偏移和多波长起振现象,而b向切割晶体则获得了中心波长近2118nm的稳定脉冲输出,且其在重复频率为20kHz时的最大平均输出功率为22.3W,脉宽为20ns,斜率效率为55.22%,光束质量因子分别为M^2_x=1.81和M^2_y=1.50。选用b向切割的Ho…YAP晶体更有利于实现稳定且高效的2118nm连续激光及纳秒级脉冲激光输出。The laser output characteristics of Ho…YAP crystal are discrepant along different cutting directions.In this study,a-cut,b-cut,and c-cut 0.5%(atomic fraction)Ho…YAP crystals were used to investigate laser output characteristics.Using a thulium-doped fiber laser with a central wavelength of 1915 nm and maximum power of44.3 Wto end pump the Ho…YAP crystal along each cutting direction,continuous-wave laser power greater than20 W was achieved.For the b-cut crystal,the central wavelength of the output laser is close to 2118 nm and the maximum continuous-wave output power and slope efficiency are 23.6 Wand 61.98%,respectively.The results for the a-cut crystal are similar to those for the b-cut crystal,but the central wavelength for the c-cut crystal is 2129 nm when the maximum output laser power is achieved.When the Ho…YAP laser operates in an in-cavity acousticoptical Q-switched state,central wavelength shifting and multi-wavelength resonance occur in the a-cut and c-cut crystals.However,for the b-cut crystal,a stable pulsed laser output with a central wavelength close to 2118 nm can be obtained.For a pulse repetition rate of 20 kHz,the maximum average output power,pulse width,slope efficiency,and beam quality factor are 22.3 W,20 ns,55.22%,M^2_x=1.81,and M^2_y=1.50,respectively.From these results,it can be concluded that the b-cut Ho…YAP crystal is more suitable for obtaining stable and efficient2118-nm continuous-wave lasers and nanosecond-level pulsed laser output.

关 键 词：材料 Ho\:YAP晶体 输出特性 切割方向 2ΜM激光 

分 类 号：TN248[电子电信—物理电子学]