Optical vortex trajectories as probes for wavefront aberrations.

Abstract

Phase singularities, due to their high sensitivity to phase disturbances, are a promising tool for wavefront retrieval. Several methods have been proposed to exploit this property, one of which analyzes their trajectories-the paths that singular points follow when shifted off-axis. Nevertheless, the relations between primary aberrations and trajectories remain unexploited. In this work, we aimed to address this gap by investigating how distinct aberrations influence vortex trajectory behavior. We performed numerical simulations of vortex trajectories under manually introduced aberrations and proposed metrics to describe their relationship. Our results show that defocus, coma, and astigmatism each produce a unique trajectory response, allowing differentiation between aberration types present in the beam. We proposed and experimentally validated an autofocusing algorithm that leverages the trajectory shape to identify the back focal plane of the optical system. This work presents a comprehensive study of optical vortex trajectories to further advance wavefront sensing based on phase singularities.