基于离焦光栅的波前传感器具有全光学测量、光路简单、使用方便和受机械振动影响小等优点, 在波前传感领域有着巨大的应用潜力。然而传统基于离焦光栅的波前复原算法仅适用于点目标的场合, 对扩展目标的波前无能为力。为了扩展该技术的应用领域, 提出一种基于离焦光栅的最小二乘波前复原算法, 该算法不仅适用于点目标的波前复原, 而且适用于扩展目标的波前复原与目标像的重建。给出了波前复原过程的数值仿真, 在理想情况下, 复原结果的均方根误差为0.18%。另外分析了影响复原精度的主要因素, 并与传统算法进行对比分析。结果表明, 新算法能够准确地对点目标和扩展目标进行波前复原。

The wavefront sensor based on defocusing grating has a great potential in the field of wavefront sensing, which attributes to many advantages such as fully optical measurement, simple configuration, ease to use, insensitivity to vibration and so on. However, traditional algorithms are suitable for point target and scarcely for extended object. To widen the application of this technology, a least square phase retrieval algorithm is proposed, which is suitable not only for point target but also for extended target, and the object can be restored simultaneously. Numerical simulations of phase retrieval using the proposed method demonstrate that the root mean square error is 0.18% without the consideration of noise. Additionally, the main factors which affect the retrieval accuracy are analyzed and some comparisons with traditional algorithms are carried out. Results show that the least square phase retrieval algorithm can accurately retrieve the wave-front of a point target or an extended target.