Simultaneous adaptive control of dual deformable mirrors for full-field beam shaping with the improved stochastic parallel gradient descent algorithm

Abstract

We propose and demonstrate the simultaneous adaptive control of a dual deformable mirror system for full-field beam shaping based on an improved stochastic parallel gradient descent (SPGD) algorithm and dual-phase-only liquid crystal spatial light modulators (LC-SLMs). One LC-SLM adaptively redistributes the intensity of the input beam and the other adaptively compensates the wavefront of the output beam. However, the intensity redistribution and wavefront compensation closed loops run simultaneously. In addition, the intensity redistribution and wavefront compensation closed loops adopt their respective metric functions independently. Experimental results show that the improved SPGD algorithm can not only be used for controlling dual deformable mirror configuration to adaptively generate near diffraction-limited flattop beams with desired intensity distributions, but also can greatly improve the control bandwidth.