高功率声光调Q1314nmNd∶YLF激光器  

High-Power Acoustol-Optic Q-Switched Nd∶YLF Laser Operating aatt 1314 nm

作　　者：张明龙 蒋聪 代世波 周海琼 朱思祁[1] 尹浩[1] 李真[1] 陈振强[1] Zhang Minglong;Jiang Cong;Dai Shibo;Zhou Haiqiong;Zhu Siqi;Yin Hao;Li Zhen;Chen Zhengqiang(Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communication Technology,Guangdong Provincial Engineering Research Center of Crystal and Laser Technology,Department of Optoelectronic Engineering,College of Science and Technology,Jinan University,Guangzhou 510632,Guangdong,China)

机构地区：[1]暨南大学理工学院光电工程系广东省晶体材料与激光技术及应用工程技术研究中心光纤传感与通信技术广东省重点实验室,广东广州510632

出　　处：《中国激光》2023年第2期22-28,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(62175093,62175091,61935010);广东省基础与应用基础研究基金(2020A1515110001);广东省重点领域研发计划(2020B090922006);广州市科技计划项目(202102020949,201904010294)。

摘　　要：采用波长锁定的窄线宽880 nm激光二极管(LD)作为泵浦源,通过单块Nd∶YLF晶体实现了稳定、高效的1314 nm激光输出。当入射泵浦功率为70 W时,得到了20.4 W的连续激光输出,光光转换效率为29.1%,光束质量因子为Mx2=1.65和My2=1.81,连续测量1 h的功率稳定性(均方根值)优于0.1%。进一步,通过在谐振腔内插入声光调制器,实现了主动调Q运转。当重复频率为20 kHz时,获得的最大平均输出功率为16.5 W,脉冲宽度为433 ns;当重复频率为1 kHz时,获得的最高单脉冲能量为9.8 mJ,脉冲宽度为119 ns。在调Q激光输出功率最高时,测量1 h的功率稳定性(均方根值)为1.2%。Objective Lasers emitted in the 1.3μm spectral region have received significant attention owing to increasing applications in remote sensing,timing systems,dermatologic procedures,and nonlinear frequency conversion.It is well known that Nd∶YLF is a promising material for generating high-energy 1.3μm pulsed laser because of its extended upperlaser-level lifetime.However,the power scaling of 1.3μm Nd∶YLF lasers is challenging because of their small stimulated emission cross-section and low thermal fracture limit.An end-pumped scheme with a broadband 880 nm laser diode(LD) is investigated to overcome these limitations.However,the power stability of the 1314 nm laser is reduced by the thermal wavelength shift and linewidth fluctuation of the broadband LD.When the broadband LD is used as the pump source,it is difficult to simultaneously improve the pump absorption efficiency,enhance the mode-to-pump overlap efficiency,and reduce the thermal stress of the laser crystal.Therefore,the high-power,high-efficiency laser output is greatly restricted.This paper introduces a wavelength-locked narrowband 880 nm LD as the pump source for generating a stable,efficient,and powerful 1314 nm laser.Methods Figure 1 shows the experimental setup.The pump source is a fiber Bragg grating(FBG) locked narrowband fiber-coupled LD with a numerical aperture of 0.22μm and a core diameter of 200μm.Its center wavelength is stabilized at 879.9 nm with a narrow spectral bandwidth of 0.2 nm.A pair of coupling lenses with 1:5 magnification is used to reimage the pump beam with a spot diameter of approximately 1 mm into the gain medium.An a-cut 1.0%(atomic fraction) Nd∶YLF crystal with a size of 3 mm×3 mm×30 mm is selected as the gain medium,which is coated for high transmission at 880 nm and 1047-1321 nm on the entrance surface and high transmission at 1047-1321 nm and partial reflectivity at 880 nm(reflectivity R≈60%) on the rear surface.Under non-lasing conditions,the pump absorption efficiency exceeds 90%.During the experiments,the

关 键 词：激光器 1314 nm激光 端面泵浦结构 Nd∶YLF晶体 声光调Q技术 

分 类 号：TN248.1[电子电信—物理电子学]