Surface solitons in quasiperiodic nonlinear photonic lattices

TL;DR

This paper investigates discrete surface solitons in one-dimensional quasiperiodic nonlinear photonic lattices, analyzing localized surface modes and their dependence on nonlinearity and quasiperiodic strength, with implications for optical localization.

Contribution

It introduces the study of surface solitons in quasiperiodic nonlinear waveguide arrays, highlighting asymmetries and localization conditions not previously explored.

Findings

Surface solitons exhibit asymmetry between focusing and defocusing nonlinearities.

Lower quasiperiodic strength is needed for surface localization compared to bulk.

Less optical power is required to localize excitation at the surface than inside the bulk.

Abstract

We study discrete surface solitons in semi-infinite, one-dimensional, nonlinear (Kerr), quasiperiodic waveguide arrays of the Fibonacci and Aubry-Andr\'e types, and explore different families of localized surface modes, as a function of optical power content (`nonlinearity') and quasiperiodic strength (`disorder'). We find a strong asymmetry in the power content of the mode as a function of the propagation constant, between the cases of focussing and defocussing nonlinearity, in both models. We also examine the dynamical evolution of a completely-localized initial excitation at the array surface. We find that in general, for a given optical power, a smaller quasiperiodic strength is required to effect localization at the surface than in the bulk. Also, for fixed quasiperiodic strength, a smaller optical power is needed to localize the excitation at the edge than inside the bulk.