纳米激光器测尺中猫眼腔的优化设计

由双面增透的凸透镜和凹面全反镜组成的猫眼逆反器（CER），替代传统平凹腔中的平面腔镜可构成一具有较佳失调特性的猫眼腔（CEC）。根据腔中稳定振荡高斯光束的自再现特性，对腔内各处的q参量进行分析，证明了束腰刚好处于猫眼腔中凸透镜的位置，因此猫眼系统可用几何光学成像公式进行设计。但因光学加工或装配等误差，传统的光腔参量选择的经验公式不再适用，所以还利用了光线追迹和空间衍射计算方法对光腔参量的最佳选择进行分析。分析表明在其他参量不变的情况下，增加凹面输出镜曲率半径可较好地改善激光横场模式。最后对分析进行了实验验证。

Optimizing Design of the Cat''''s Eye Cavity in a Nanometer Laser Ruler

Replacing the plane cavity mirror in a traditional plane-concave cavity by a cat′s eye retroreflector (CER), which consists of a convex lens and a concave reflective mirror, the cavity forms a cat′s eye cavity (CEC) with a higher misalignment tolerance. Based on the theory of self-reproducing of stably oscillating Gaussian beams in the cavity, the q parameters inside the cavity are analyzed. The result shows that the beam waist exactly locates at the position of the convex lens. Hence, the CER can be designed by using the geometrical optics imaging formulas. However, because of the errors of optical manufacture and assembly, the traditional experience formulas are no more suitable for the selection of the cavity parameters, so, by using the method of ray tracing and spatial diffractive calculation, how to optimize the cavity parameters is also analyzed. The analysis indicates that the increase of the radius of curvature of the concave output mirror can effectively improve the transverse mode. The analysis was proved by the experiment.