摘要
During the propagation of high-power lasers within internal channels,the laser beam heats the propagation medium,causing the thermal blooming effect that degrades the beam quality at the output.The intricate configuration of the optical path within the internal channel necessitates complex and time-consuming efforts to assess the impact of thermal blooming effect on the optical path.To meet the engineering need for rapid evaluation of thermal blooming effect in optical paths,this study proposed a rapid simulation method for the thermal blooming effect in internal optical paths based on the finite element method.This method discretized the fluid region into infinitesimal elements and employed finite element method for flow field analysis.A simplified analytical model of the flow field region in complex internal channels was established,and regions with similar thermal blooming effect were divided within this model.Based on the calculated optical path differences within these regions,numerical simulations of phase distortion caused by thermal blooming were conducted.The calculated result were compared with those obtained using the existing methods.The findings reveal that for complex optical paths,the discrepancy between the two approaches is less than 3.6%,with similar phase distortion patterns observed.For L-type units,this method and the existing methods identify the same primary factors influencing aberrations and exhibit consistent trends in their variation.This method was used to analyze the impact of thermal blooming effect in a straight channel under different gravity directions.The results show that phase distortion varies with changes in the direction of gravity,and the magnitude of the phase difference is strongly correlated with the component of gravity perpendicular to the optical axis.Compared to the existing methods,this approach offers greater flexibility,obviates the need for complex custom analysis programming.The analytical results of this method enable a rapid assessment of the thermal blooming effect in optical paths within the internal channel.This is especially useful during the engineering design.These results also provide crucial references for developing strategies to suppress thermal blooming effect.
高功率激光在内通道传播过程中,光束会在导光路径中对传播介质加热,从而产生热晕现象,这会影响高能激光设备出光口处光束质量。此外,由于内通道中光路排布复杂,因此对导光路径上热晕影响的评估往往需要复杂的工作和较长的时间。为适应工程中对导光路径热晕效应快速评估的需要,本文提出一种基于有限元法的内光路热晕效应快速模拟方法。该方法对流体区域进行微元划分,利用有限元分析方法进行流场分析。对复杂内通道的流场区域建立简化分析模型,在简化模型中划分等晕区域。根据各等晕区域内光程差计算结果,完成热晕效应导致的相位畸变的数值模拟计算。将计算结果与现有方法计算结果对比,结果显示:对于复杂光路,该方法计算结果与现有方法计算结果偏差小于3.6%,相位畸变形式相近;对于L型单元,该方法计算结果与现有方法计算结果得到的主要像差影响因素和变化规律相同。利用该方法完成了对直管道不同重力作用方向下的热晕影响分析,结果显示:相位畸变随重力方向变化而变化,相位变化的大小与重力在垂直于光轴方向的分量大小有很强的相关性。该方法相较于现有方法灵活性高、无需进行复杂自编分析程序调试。该方法的分析结果在工程设计阶段能够快速评估内通道导光路径中的热晕效应,为确定热晕抑制方法提供重要参考。
出处
《中国光学(中英文)》
北大核心
2025年第3期520-534,共15页
Chinese Optics
基金
吉林省科技发展计划项目(No.20230301002GX,No.20230301001GX)。
作者简介
WU Dong-yu(1999-),male,born in Shuangyashan,Heilongjiang Province,master candidate.He received his bachelor's degree from Anhui Polytechnic University in 2022.His research mainly focuses on the environmental adaptability analysis of optical precision instruments.E-mail:wudongyu1111@163.com;Corresponding author:LI Xiang(1986-),male,born in Changchun,Jilin Province.Ph.D,associate professor,and master supervisor.He received his Ph.D.from the Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences in 2015.His research mainly focuses on laser propagation,optical system structure optimization design,analysis,and environmental adaptability research.E-mail:abelfeel@163.com。
