Observation of Edge Solitons in Photonic Graphene

TL;DR

This paper reports the experimental observation of edge solitons in a reconfigurable photonic graphene lattice, demonstrating nonlinear topological photonics phenomena with potential for advanced device applications.

Contribution

It introduces the first experimental demonstration of edge solitons in a nonlinear, reconfigurable photonic graphene platform using electromagnetically induced transparency and Raman gain.

Findings

Edge solitons observed at zigzag edges of photonic graphene.

Nonlinear effects enable topological edge states to form solitons.

Reconfigurable platform allows exploration of nonlinear topological phenomena.

Abstract

Edge states emerge in diverse areas of science, offering new opportunities for the development of novel electronic or optoelectronic devices, sound and light propagation controls in acoustics and photonics. Previous experiments on edge states and exploration of topological phases in photonics were carried out mostly in linear regimes, but the current belief is that nonlinearity introduces new striking features into physics of edge states, lead-ing to the formation of edge solitons, optical isolation, and topological lasing, to name a few. Here we experimentally demonstrate edge solitons at the zigzag edge of a reconfigurable photonic graphene lattice created via the effect of electromagneti-cally induced transparency in an atomic vapor cell with controllable nonlinearity . To obtain edge solitons, Raman gain was introduced to compensate strong absorption experienced by the edge state during propagation. Our observations pave the way to ex-perimental exploration of topological photonics on nonlinear, reconfigurable platform.