Collision and fusion of counterpropagating micron-sized optical beams in non-uniformly biased photorefractive crystals

TL;DR

This paper theoretically studies how counterpropagating optical beams interact in non-uniformly biased photorefractive crystals, predicting conditions for their fusion or formation of curved light channels based on voltage modulation.

Contribution

It introduces a theoretical framework for beam collision and fusion in photorefractive crystals with spatially varying bias voltages, highlighting the effects of voltage modulation speed.

Findings

Rapid voltage modulation suppresses self-bending, enabling soliton fusion.

Slow voltage modulation allows self-bending, leading to curved light-channel formation.

Analytical predictions align with potential experimental configurations.

Abstract

We theoretically investigate collision of optical beams travelling in opposite directions through a centrosymmetric photorefractive crystal biased by a spatially non-uniform voltage. We analytically predict the fusion of counterpropagating solitons in conditions in which the applied voltage is rapidly modulated along the propagation axis, so that self-bending is suppressed by the "restoring symmetry" mechanism. Moreover, when the applied voltage is slowly modulated, we predict that the modified self-bending allows conditions in which the two beams fuse together, forming a curved light-channel splice.