Mansell J D, Gustafson E K
Appl Opt. 2001 Mar 1;40(7):1074-9. doi: 10.1364/ao.40.001074.
During construction of a Shack-Hartmann wave-front sensor it is critical that the spacing between the lens array and the detector array be equal to the lens array focal length to obtain accurate and precise measurements of a wave front. This separation is often difficult to determine with large f/# lenses, because their focal spot diameter does not change substantially for small displacements on either side of the focal plane. We describe a method with an array of off-axis lens segments for determining the location of the focal plane. Because the lenses are off axis, changes in the distance from the optic to the detector array result in transverse focal spot position variations as a function of their separation from the lenses. By analyzing the focal spot pattern on a CCD, we achieved 12-mum rms error in the axial position measurement while moving a 4-mm-focal-length optic over 1 mm.
在构建夏克-哈特曼波前传感器时，透镜阵列与探测器阵列之间的间距必须等于透镜阵列的焦距，才能获得准确且精确的波前测量结果，这一点至关重要。对于大f/#透镜，这种间距通常很难确定，因为在焦平面两侧进行小位移时，它们的焦斑直径变化不大。我们描述了一种使用离轴透镜段阵列来确定焦平面位置的方法。由于透镜是离轴的，从光学器件到探测器阵列的距离变化会导致横向焦斑位置随其与透镜间距的变化而变化。通过分析电荷耦合器件（CCD）上的焦斑图案，在移动一个4毫米焦距的光学器件超过1毫米的过程中，我们在轴向位置测量中实现了均方根误差为12微米。
