Fourier-plane wavefront and SLM aberration characterization via iterative scanning of beam deflector segments.

Abstract

This study presents a method for characterizing the effective incident wavefront in the Fourier plane, eliminating the need to decouple measurement and application. The amplitude and phase of this wavefront are cumulatively affected by the incident beam, the curvature of the backplane, and the defocus introduced by the Fourier lens. Using an iterative camera-in-the-loop approach, this method displays square patches of beam deflection phase ramps on the spatial light modulators (SLMs), and the resultant spots in the Fourier plane are positionally controlled. The parameters of each patch are used to reconstruct the phase and amplitude profiles of the wavefront. These profiles are used in hologram computation to correct for SLM aberrations and improve image quality. The proposed method has been experimentally verified to work with off-axis and on-axis optical systems, showing the versatility of the approach.