Two-dimensional solitons at interfaces between binary superlattices and homogeneous lattices

TL;DR

This paper experimentally demonstrates two-dimensional surface solitons at the interface of a homogeneous lattice and a binary superlattice, revealing power differences based on waveguide depth and asymmetric output patterns.

Contribution

It presents the first experimental observation of 2D surface solitons at such an interface, highlighting the impact of waveguide depth on soliton power requirements.

Findings

Deep site solitons require lower power than shallow site solitons.

Interface causes asymmetric output patterns despite equal average refractive index.

Surface solitons are observed at the boundary between different lattice types.

Abstract

We report on the experimental observation of two-dimensional surface solitons residing at the interface between a homogeneous square lattice and a superlattice that consists of alternating "deep" and "shallow" waveguides. By exciting single waveguides in the first row of the superlattice, we show that solitons centered on deep sites require much lower powers than their respective counterparts centered on shallow sites. Despite the fact that the average refractive index of the superlattice waveguides is equal to the refractive index of the homogeneous lattice, the interface results in clearly asymmetric output patterns.