Performance improvement of the feedback-based wavefront shaping in second-harmonic generation

The fundamental beam wavefront shaping method is developed to increase the nonlinear frequency convention efficiency and control of the nonlinear beam profile. In this work, a method is presented to accelerate the procedure of optimizing the wavefront phase of the fundamental beam to approach the maximum second-harmonic generation (SHG) efficiency. Furthermore, this method allows use of high-resolution spatial phase modulators for wavefront shaping while the number of phase optimization variables remains limited. The obtained results show that the presented method reduces the amount of the needed feedback by 3 orders of magnitudes while the SHG efficiency is improved twice.