基于全固态单向行波环形腔的连续波单频1.5μm激光器  

Continuous-Wave Single-Frequency 1.5μm Laser Based on All-Solid-State Unidirectional Traveling-Wave Ring Cavity

作　　者：姚子健 李渊骥[1,2] 宋政 冯晋霞 张宽收[1,2] Yao Zijian;Li Yuanji;Song Zheng;Feng Jinxia;Zhang Kuanshou(State Key Laboratory of Quantum Optics and Quantum Optics Devices,Institute of Opto-Electronics,Shanxi University,Taiyuan,Shanxi 030006,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan,Shanxi 030006,China)

机构地区：[1]山西大学光电研究所量子光学与光量子器件国家重点实验室,山西太原030006 [2]山西大学极端光学协同创新中心,山西太原030006

出　　处：《中国激光》2021年第5期159-167,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划(2017YFB0405203,2016YFA0301401)。

摘　　要：报道了一台激光二极管双端端面偏振抽运的低噪声单向行波环形腔连续波单频Er,Yb∶YAB 1.5μm激光器。通过精确测量蓝宝石-Er,Yb∶YAB-蓝宝石薄片和铋铁石榴石磁光晶体的热透镜焦距,采用双端面、长聚焦、偏振选择的抽运结构,通过提高可注入的抽运功率、降低激光晶体的热效应,首次实现了基于单向行波环形腔单纵模选择技术的全固态连续波单频1.5μm激光运转。连续波单频1.5μm激光输出功率达755 mW,2 h内的功率波动小于±1.2%,激光的强度噪声在分析频率大于5 MHz的范围内达到散粒噪声极限。Objective High power and low noise continuous-wave(CW)single-frequency all-solid-state lasers at 1.5μm have important applications in laser interferometry,coherent Doppler lidar,optical frequency standard,cold atom physics,continuous variable(CV)quantum information,and basic research of quantum optics.1.5μm lasers with power more than 500 mW and an intensity noise spectrum down to the shot-noise limit are indispensable in the development of telecom band quantum light sources,e.g.,CV entangled states.The diode-pumped all-solid-state CW single-frequency 1.5μm lasers were mainly developed using the Er^(3+)and Yb^(3+)co-doped gain mediums and the longitudinal mode selection techniques,such as intracavity etalon,microchip cavity,or twisted-mode cavity.This kind of laser suffers from the relatively low thermal fracture threshold and significant thermal-induced depolarization,and the deterioration of beam quality and longitudinal mode structure.There is no report on a CW single-frequency all-solid-state laser at 1.5μm providing low noise output more than 500 mW.Methods To achieve high power CW single-frequency laser operation at 1.5μm,the heat deposition inside the gain medium was firstly reduced by a dual-end face-cooling scheme,i.e.,using two polished sapphire plates acting as transparent heat spreaders to improve the axial heat conduction in the Er,Yb∶YAB crystal.Secondly,to realize a relatively homogeneous distribution of pump absorption inside the gain medium,and to raise the maximum permitted incident pump power and achieve the best mode-matching,a long depth-of-focus polarized dual-end-pump structure was employed(Fig.1,Fig.2).Finally,two additional half-wave plates were used to control the pump polarization.Due to the dependence of absorption on the polarization,the pump power axial absorption can be tuned to be more uniform,and the pump saturation effect can be prevented.The designed ring resonator was based on the precise measurements of the thermal focal lengths of both the laser crystal and the bismuth

关 键 词：激光器 1.5μm激光 连续波单频 单向行波环形腔 低噪声 

分 类 号：TN248.1[电子电信—物理电子学]