Unraveling beam self-healing

TL;DR

This paper reveals that various optical beams, including Gaussian beams, can self-reconstruct after encountering obstacles, by analyzing the underlying physics, proposing a new minimum reconstruction distance, and introducing a quantitative measure of self-healing.

Contribution

It provides a comprehensive mathematical and physical framework for beam self-healing, extending beyond diffraction-free beams, and introduces a novel degree of self-healing based on amplitude comparison.

Findings

Gaussian beams can self-reconstruct after obstruction

A new minimum reconstruction distance is defined

An experimental technique using Shack-Hartmann wavefront reconstruction is demonstrated

Abstract

We show that, contrary to popular belief, non only diffraction-free beams may reconstruct themselves after hitting an opaque obstacle but also, for example, Gaussian beams. We unravel the mathematics and the physics underlying the self-reconstruction mechanism and we provide for a novel definition for the minimum reconstruction distance beyond geometric optics, which is in principle applicable to any optical beam that admits an angular spectrum representation. Moreover, we propose to quantify the self-reconstruction ability of a beam via a newly established degree of self-healing. This is defined via a comparison between the amplitudes, as opposite to intensities, of the original beam and the obstructed one. Such comparison is experimentally accomplished by tailoring an innovative experimental technique based upon Shack-Hartmann wave front reconstruction. We believe that these results can open new avenues in this field.