Truncated-Bloch-wave solitons in optical lattices

TL;DR

This paper investigates the existence, stability, and characteristics of truncated Bloch-wave solitons in one-dimensional optical lattices, revealing stable and unstable families and their spectral properties.

Contribution

It introduces the concept of truncated Bloch-wave solitons in optical lattices and analyzes their bifurcation and stability properties, which were not previously characterized.

Findings

Families of localized states differ by the number of peaks

Lower branch states are stable in deep potentials

Upper branch states are unstable regardless of peaks

Abstract

We study self-trapped localized nonlinear states in the form of truncated Bloch waves in one-dimensional optical lattices, which appear in the gaps of the linear bandgap spectrum. We demonstrate the existence of families of such localized states which differ by the number of intensity peaks. These families do not bifurcate from the band edge, and their power curves exhibit double branches. Linear stability analysis demonstrates that in deep lattice potentials the states corresponding to the lower branches are stable, whereas those corresponding to the upper branches are unstable, independently of the number of peaks.