Self-healing and transformation characteristics of obstructed Hermite-Gaussian modes composed structured beams

TL;DR

This paper investigates the self-healing and transformation behaviors of obstructed Hermite-Gaussian structured beams, revealing their ability to recover or transform after partial obstruction through diffraction and interference, with experimental validation.

Contribution

It provides a theoretical and experimental analysis of self-healing in obstructed HG modes, including the effects of incoherent and coherent superpositions, expanding potential applications.

Findings

Partially obstructed HG modes can recover or transform in the far-field.

Self-healing is driven by diffraction and interference effects.

Incoherent superpositions show strong self-recovery ability.

Abstract

The self-healing property of laser beams is of great interest. And a laser beam with spatial structures is also widely concerned due to its important applications in lots of areas. We theoretically and experimentally investigate the self-healing and transformation characteristics of obstructed structured beams composed by incoherent or coherent superposition of multiple Hermite-Gaussian (HG) modes. We reveal that partially obstructed single HG mode can recover itself or transfer to a lower order in the far-field. When the obstacle retains one pair of edged bright spots of HG mode in each direction of its two symmetry axes, the beam structure information (number of knot lines) along each axis can be restored. Otherwise, it will be transferred to the corresponding low-order HG mode or multi interference fringes in the far-field, according to the interval of the two most edged remaining spots on each axis. It's proved that the above effect is induced by the diffraction and interference results of the partially retained light field. This principle is also applicable to multi-eigenmodes composed beams with special customized optical structures. Then the self-healing and transformation characteristics of the partially obstructed HG modes composed structured beams are investigated. It's found that the HG modes incoherently composed structured beams have a strong ability to recover themselves in the far-field after occlusion. These investigations can expand the applications of optical lattice structures of laser communication, atom optical capture, and optical imaging.