晶体几何结构及入射角度对自抽运相位共轭特性影响的研究

Investigation of Influence of Incident Angle and Crystal Geometrical Configuration on Self-Pumped Phase Conjugation Properties

基于两块不同尺寸的Cu∶KNSBN晶体自抽运相位共轭实验,研究了光折变晶体的几何结构及入射角度对自抽运相位共轭特性的影响,得到在入射位置不变化的情况下,随着入射角度的变化相位共轭光输出有最大值,几何结构不同对应的最大值不同。并从理论上分析了晶体结构及入射角度在双作用区自抽运相位共轭机理中的作用,指出几何结构、入射角度与自抽运光通道、耦合系数的关系,及在自抽运相位共轭效应中存在一个最佳入射角度,这时相位共轭光输出最大。最后,对理论上的相位共轭反射率公式进行了修正。对自抽运相位共轭实际应用中,选择最佳入射角度提供了理论和实验依据。

Based on self-pumped phase conjugation experiment in two blocks of Cu2 KNSBN crystal, the influence of the incident angle and photorefractive crystal geometrical configuration on self-pumped phase conjugation properties is investigated. The maximum output of phase conjugation is found with variety in the incident angle for the same incident position. The different configurations determine different maximum output. The action of crystal geometrical configuration and incident angle in dual active regions self-pumped phase conjugation mechanism is analyzed theoretically. The relation between geometrical configuration and incident angle and self-pumped beam path and beam-coupling coefficient is built. The optimal incident angle for maximum output of phase conjugation light is given in self-pumped phase conjugation effect. Finally, the formula of reflectivity of phase conjugation beam is modified. The research lays foundation of theory and experiment for selecting the optimal incident angle in fact.