长焦距红外光学系统焦距检测方法

Method of focal length measurement for infrared optical system with long focal length

强激光主机装置中,需要利用各种不同焦距的光学透镜对光束进行扩束和准直,透镜焦距的准确程度直接影响系统的整体性能,所以对透镜焦距的准确测量尤为重要。提出了一种利用哈特曼-夏克波前检测仪和旋转平面镜辅助测量长焦距红外光学系统焦距的新方法。给出了系统的测量原理,使用ZEMAX光学仿真软件仿真分析了待测透镜不同通光孔径对焦距测量的影响,并且通过误差理论推导出平面镜旋转角度与系统测量误差之间的解析表达式。最后进行了实验对比,测量结果表明,当平面镜旋转至一定角度,采用合适的通光口径,系统测量精度可以优于3‰,远高于传统测量方法。此外,该测量方法还具有使用方便、高稳定度等显著优点。

In strong laser host device, various optical lens with different focal length are needed to expand and collimate the beam, the accurate of the lens＇ focal length directly affect the overall performance of the system, so it is particularly important to accurately measure the focal length of lens. A new method of measuring the infrared optical system with long focal length by using the Hartmann- Shack wave-front detected device and rotated plane mirror was proposed. The measuring principle of the system was given. Using optical simulation software ZEMAX, the influence of different aperture on the measurement of focal length was analyzed. Then the relationship between the rotation angle of the plane mirror and the system measurement error was deducted by using error theory. Finally the experiment was done to obtain the real result, the result of measurement shows that when the plane mirror rotated to a certain angle, set an appropriate optical aperture, the system measurement precision can be better than 3‰, much higher than the traditional measuring method. In addition, the measurement method is also conveniently to use, high stability in measure, etc.