温度诱导液晶相控光束质量恶化分析

Analysis of temperature-induced liquid crystal phase control beam quality deterioration

液晶光学相控阵是下一代光束控制技术的核心器件,提高其耐受激光阈值是当前研究的热点之一。针对较高功率激光入射场景下评测液晶光学相控阵相位调制性能恶化程度的问题,本文基于传统四分之一波片法,实现快速、直接测量液晶对入射激光的相位调制量。验证试验发现,当中心温度为33℃时,对应的最大畸变相位为3.6 rad。同时,本文基于该实测相位调制结果,研究出射光的光束质量恶化过程。分析结果表明:当液晶移相器的中心温度变化小于10℃时,光束质量恶化小于20%。

The liquid crystal optical phased array(LCOPA)is the core device of next-generation beam control tech-nology.Improving its laser-induced damage threshold is one of the current research hot spots.Aiming at the scene of higher power laser incidence,the degradation degree of LCOPA phase modulation performance should be evaluated.Based on the traditional quarter-wave plate method,this paper realizes fast and direct measurement of the phase modulation of the liquid crystal to the incident laser.The verification test found that when the core temperature is 33℃,the corresponding maximum phase aberration is 3.6 rad.At the same time,based on the measured phase modulation results,this paper studies the deterioration process of the beam quality of the outgoing light.Analysis results show that the deterioration of beam quality is less than 20%when the core temperature of the liquid crystal phase shifter changes less than 10℃.