增大夏克-哈特曼波前传感器动态测量范围的方法

Extrapolation method to extend dynamic range of Shack-Hartmann wave-front sensor

为了使夏克-哈特曼波前传感器(HS)在具有高灵敏的同时又能获得大的动态测量范围,介绍了一种能够增大HS动态测试范围的软件处理方法-外推法。在运用外推法时,首先需要找出任意子孔径(A)对应的焦斑位置作为起始点,然后利用外推法得到与A相邻的子孔径(B)内的焦斑位置,再以B内的焦斑位置作为起始点外推得到与B相邻的其它子孔径内的焦斑位置,依次类推,直至把所有子孔径内的焦斑全部找到。文中利用实验对外推法的可行性和实用性进行了验证,结果表明,在超出HS动态测量范围2倍的情况下,利用外推法可以完美地复原波面,基本解决了HS的动态测量范围和灵敏度相互矛盾的问题。

A software-based method called extrapolation method was presented to overcome the tradeoff between the sensitivity and the dynamic range of displacement of Shack-Hartmann Wave-front Sensor （HS）. Firstly, a beginning focal-spot of a random sub-aperture （A） was obtained, and the focal-spots of the neighbor sub-apertures （B） on A were found through the extrapolation method. By taking a focal-spot of B as the beginning point, the focal-spots of the neighbor sub-apertures on B could be obtained. In the same way, the other focal-spots could also be obtained. In order to demonstrate the feasibility and practicability of the extrapolation method, an experiment was carried out. The results show that the extrapolation method can restore the wave-front while the aberration of the incident wave-front is about twice that of dynamic range of HS, which can satisfy measurement requirements for the large dynamic range and high sensitivity of HS.