摘要
仿真计算一直是研究激光器的重要手段,而激光理论是仿真计算的基础.虽然半经典激光理论能够精确地描述激光的产生过程,但是其复杂性导致仿真需要庞大的计算资源和计算时间.为了能够更加高效地对激光器进行仿真,提出了一种调Q固体激光器的仿真模型.基于此模型,研究了影响主动调Q激光产生过程的因素.这些因素包括抽运功率、抽运光分布和模式竞争.仿真计算结果与对照实验测量数据相符合,说明了模型的有效性.
Computer simulation is always an important means for studying laser, while laser theory is the basis of simulation.Although the semi-classical laser theory can accurately describe the generation process of laser, its complexity leads to a need of huge resources and time for computation. However, in particular cases, the influence of some factors on the laser system can be neglected. If a simpler model is employed to describe the laser system, the time of simulation can be shortened significantly.In order to simulate the laser system more efficiently, a simulation model of Q-switched solid-state laser is proposed in this paper. In this model, the time-domain function of Q switch is introduced, which represents the modulation of Q switch loss over time. Because the cross section of the Nd：YAG rod is circularly shaped, the resonator eigenmodes are assumed to be a Laguerre-Gaussian beam for simplicity. Then, any other laser beam can be formed by superposition of the eigenmodes of the resonator. These series of resonator eigenmodes are coupled with the rate equations of laser crystals. Finally, the distribution of pump light field inside the laser crystal is approximated as super Gaussian distribution.Based on this physical model, the influence of pump power and pump light field distribution on the output beam of multimode Q-switched solid-state laser is investigated. The simulation results are in good agreement with the experimental data, which explains the validity of the proposed model. For instance, with the increase of pump power, the output power of the laser increases, but the overall slope efficiency decreases. This is because the diffraction loss δm,n of the lower order mode is less than the diffraction loss of higher order mode. When the pumping power increases, the higher order mode that starts to oscillate has lower utilization efficiency of pump energy. Therefore, the overall slope efficiency of the laser is reduced. In order to analyze the mode competition in the multimode Q-switched solid-state laser
作者
程秋虎
王石语
过振
蔡德芳
李兵斌
Cheng Qiu-Hut Wang Shi-Yu Guo Zhen Cai De-Fang Li Bing-Bin(School of Physics and Optoelectronic Engineering, Xidian University, Xi＇an 710071, China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2017年第18期31-38,共8页
Acta Physica Sinica
基金
国防预研究基金(批准号:9140A020105)资助的课题~~
关键词
数值仿真
二极管抽运激光器
光束传输
Q开关
numerical simulation
diode-pumped lasers
wave propagation
Q-switching
