利用衍射传输矩阵分析激光介质热效应对激光模式的影响  

Influence of Thermal Effect on Laser Mode Based on Diffraction Transmission Matrix

作　　者：廉欣唯 付时尧 王庆[1,2] 高春清 Lian Xinwei;Fu Shiyao;Wang Qing;Gao Chunqing(School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China;Key Laboratory of Information Photonics Technology,Ministry of Industry and Information Technology,Beijing 100081,China)

机构地区：[1]北京理工大学光电学院,北京100081 [2]信息光子技术工业和信息化部重点实验室,北京100081

出　　处：《光学学报》2025年第1期159-168,共10页Acta Optica Sinica

基　　金：国家自然科学基金(61627821)。

摘　　要：利用衍射传输矩阵特征值方法,定量地研究了在半导体激光侧面泵浦的固体激光器中,激光介质的热效应对谐振腔横模和纵模的影响。研究发现,随着热效应的产生,各个横模的损耗整体提高,一些高阶横模的损耗低于更低阶的模式,与此同时,谐振腔的纵模间隔保持不变,而纵模位置发生偏移。Objective Solid-state lasers pumped by laser diodes have advantages including high conversion efficiency,excellent beam quality,and stable laser output.As the demand for laser power in various applications keeps increasing,the thermal effects inside the laser cavity have become a crucial factor affecting laser mode,efficiency,and beam quality.For endpumped solid-state lasers,a good match between the pump light and laser mode is beneficial for better control of the laser beam quality.In contrast,side-pumping allows for higher pump powers but has poorer pump uniformity,which can easily lead to simultaneous oscillations of multiple transverse modes.Therefore,besides homogenizing the pump distribution as much as possible,it is necessary to study the effect of uneven pump distributions and the resulting thermal effects on the resonator modes.Since side-pumping and its thermal effects may have complex and asymmetric spatial distributions,and potentially excite higher-order transverse modes,in this study,we adopt a diffraction-based method for solving the resonator modes for analysis.This method has developed rapidly since the beginning of this century,and it can simultaneously calculate a large number of eigenmodes inside the resonator and handle resonators affected by complex physical fields,thus providing abundant physical information.Methods In this study,we first introduce the transmission matrix eigenvalue method for solving the resonant cavity mode,including its mathematical form and corresponding physical meaning.Using this method,we analyze the influence of thermal effects on the modes of a laser resonant cavity that utilizes a double-end side-pumped Nd∶YAG cylindrical crystal as the gain medium.In this process,a mathematical model for the double-end side-pumped power distribution is established,and the temperature and strain distributions within the gain crystal are obtained through finite element analysis(FEA).Then,the spatial phase modulation of the laser caused by the gain crystal,which results from end-s

关 键 词：固体激光 热效应 特征值方法 模式分布 衍射 

分 类 号：TN248.1[电子电信—物理电子学]