Formation of discrete solitons in light-induced photonic lattices

Zhigang Chen,Hector Martin,Jianke Yang,Jingjun Xu,Eugenia D Eugenieva

doi:10.1364/opex.13.001816

Abstract

We present both experimental and theoretical results on discrete solitons in two-dimensional optically-induced photonic lattices in a variety of settings, including fundamental discrete solitons, vector-like discrete solitons, discrete dipole solitons, and discrete soliton trains. In each case, a clear transition from two-dimensional discrete diffraction to discrete trapping is demonstrated with a waveguide lattice induced by partially coherent light in a bulk photorefractive crystal. Our experimental results are in good agreement with the theoretical analysis of these effects.

Highlights

Nonlinear discrete systems are abundant in nature
When the waveguide array is embedded in a nonlinear medium, a balance between discrete diffraction and nonlinear self-focusing gives rise to a localized state of light better known as "discrete solitons" [3]
This soon led to various experimental observations of Discrete solitons (DS) in such waveguide arrays established with optical induction, either via coherent beam interference [7,8,9] or via amplitude modulation of a partially coherent beam [10, 11]

Summary

Introduction

Nonlinear discrete systems are abundant in nature. In optics, a typical example is a closelyspaced nonlinear waveguide array, in which collective behavior of wave propagation exhibits many intriguing phenomena [1, 2]. Different from previous experiments in which the lattice is created by coherent multi-beam interference [79], the DS reported here are hosted in a partially incoherent photonic lattice This in turn enables stable lattice formation due to suppression of incoherent modulation instability [16]. The amplitude mask provides spatial modulation after the diffuser on the otherwise uniform beam, which exhibits a pixel-like intensity pattern at the input face of the crystal [17]. Another beam split from the same laser but without going through the diffuser is used as the probe beam, propagating along with the lattice. As the bias field is increased to more than 3 kV/cm, the lattice structure remains nearly invariant, except a slight change in its contrast at high bias due to nonzero r13

Fundamental discrete solitons

Discrete dipole and vector solitons

Discrete soliton trains

Summary