Vector solitons in nonlinear isotropic chiral metamaterials

TL;DR

This paper derives coupled nonlinear Schrödinger equations for electromagnetic fields in nonlinear chiral metamaterials, revealing conditions for vector soliton formation, including bright and dark types, within specific spectral regimes.

Contribution

It introduces a novel derivation of coupled NLS equations for Beltrami components in nonlinear chiral metamaterials and identifies spectral regimes supporting vector solitons.

Findings

Existence of negative refractive index in certain spectral regimes.

Approximation of the system by the Manakov model in a subregime.

Formation of bright and dark vector solitons in the metamaterials.

Abstract

Starting from the Maxwell equations, we used the reductive perturbation method to derive a system of two coupled nonlinear Schr\"{o}dinger (NLS) equations for the two Beltrami components of the electromagnetic field propagating along a fixed direction in an isotropic nonlinear chiral metamaterial. With single-resonance Lorentz models for the permittivity and permeability and a Condon model for the chirality parameter, in certain spectral regimes, one of the two Beltrami components exhibits a negative real refractive index when nonlinearity is ignored and the chirality parameter is sufficiently large.We found that, inside such a spectral regime, there may exist a subregime wherein the system of the NLS equations can be approximated by the Manakov system. Bright-bright, dark-dark, and dark-bright vector solitons can be formed in that spectral subregime.