激光束经离轴抛物面镜聚焦后光斑特性的研究  

Study on Focusing Spot Characteristic by Off-axis Parabolic Mirror

作　　者：石鸿斌[1] 程兆谷[1] 许国良[1] 蒋金波[1] 李现勤[1] 夏金安[1] 

机构地区：[1]中国科学院上海光机所,上海201800

出　　处：《中国激光》2000年第10期880-886,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(批准号:69978022)资助项目

摘　　要：从几何光学和物理光学出发 ,对抛物面镜以离轴 90°的方式应用于激光束的聚焦光路时 ,光轴的角度失准和入射光发散角对聚焦光斑造成的影响进行了分析 .基模高斯光准直入射时 ,由于抛物面镜无球差 ,焦斑的峰值光强将与入射光直径的平方成正比 .光线追迹法证明角度失准导致产生一对相互垂直的焦线 ,由衍射光学知入射的高斯光将转变为类椭圆高斯光 ,降低了焦面处的峰值光强 .抛物面镜对入射角失准的敏感度极高 ,mrad量级的误差就足以使焦面处的峰值光强降低一半左右 .而且 ,入射光束直径的增大又将大幅度降低对角度失准的容忍度 ,使焦面处的峰值光强对失准更敏感 .同时也证明发散角的存在将导致产生彗差 。Based on combining geometrical and physical optics, the effects of the angular misalignment of the optical axis and divergence angle on the focal power density are analyzed. Ray tracing analysis proves that a pair of focal lines are produced due to the angular misalignment, and diffractive optics proves that incident beam of Gaussian mode brings about reflective beam of near elliptical Gaussian mode. So that, the focal power density is decreased due to the angular misalignment. The parabolic mirror is very sensitive to misalignment, and the misalignment angle of the order of mrad magnitude is enough to decrease peak power density down to the half. The tolerance of the misalignment angle goes rapidly down with the incident beam diameter increasing. When the incident angle has a divergence angle, coma is produced to decrease the power density at focal plane.

关 键 词：抛物面镜 离轴 角度失准 发散角 

分 类 号：TH74[机械工程—光学工程]