Orbital angular momentum beam instabilities in engineered nonlinear colloidal media

TL;DR

This study experimentally investigates how optical vortex beams with different topological charges evolve in engineered nonlinear colloidal media, revealing instability-driven splitting into necklace beams and potential applications in optical manipulation.

Contribution

It demonstrates the experimental observation of vortex beam instabilities and their agreement with theoretical predictions in engineered nonlinear colloidal suspensions.

Findings

Vortex beams split into necklace patterns due to modulation instability.

Number of bright spots correlates with the topological charge.

Results align with linear stability analysis and simulations.

Abstract

In this letter, we experimentally demonstrate the evolution of the optical vortex beams of different topological charges propagating in engineered nano-colloidal suspension of negative polarizability with saturable nonlinearities. Due to the high power of the incident beam, the modulation instability leads to an exponential growth of weak perturbations and thus splits the original vortex beam into a necklace beam consisting of several bright spots. The number of observed bright spots is intrinsically determined by the topological charge of the incident beam and agrees well with the predictions of our linear stability analysis and numerical simulations. Besides contributing to the fundamental science of light-matter interactions in engineered soft-matter media, this work opens new opportunities for dynamic optical manipulation and transmission of light through scattering media as well as formation of complex optical patterns and light filamentation in naturally existing colloids such as fog and clouds.