Experimental study of wavefront sensorless adaptive optics based on deformable mirror eigen modes

The wavefront correction methods in wavefront sensorless adaptive optics can be classified into two groups: model-free optimization algorithms and modal-based optimization algorithms. In this paper, the feasibility of optimization algorithm based on deformable mirror (DM) eigen modes is verified by the experiments. Experimental results show that the correction accuracy of algorithm using DM eigen modes is higher than that of using Lukosz modes because the mode fitting error can be avoided. Since the correction amount of each DM eigen mode can be estimated independently, a proper mode number is chosen according to the spatial frequency contents in initial wavefront aberration to improve the correction speed. Compared with the commonly used stochastic parallel gradient descent (SPGD) algorithm, the correction accuracy of modal-based algorithm is nearly the same as it, but the correction speed is improved by one order of magnitude.