Cross-talk compensation of a spatial light modulator for iterative phase retrieval applications

Beam-propagation-based phase recovery approaches, also known as phase retrieval methods, retrieve the amplitude and the phase of arbitrary complex-valued fields. We present and experimentally demonstrate a simple and robust iterative method using a liquid crystal spatial light modulator located at an object diffraction plane. M random phase masks are applied between the object and the image sensor using the modulator, and then M diffraction patterns are collected in the Fourier plane. An iterative algorithm using these patterns and simulating the propagation of the light between the two planes allow us to recover the object wavefront. The use of this type of dynamic modulator makes the experimental setup simpler and more flexible. We need no a priori knowledge about the object field, and the convergence rate is high. Simulation results show that the method exhibits high immunity to noise and does not suffer any stagnation problem. However, experimental results have shown that the technique is sensitive to the cross talk of the modulator. We propose a method for compensating these modulator defects that are validated by experimental results.