Free-carrier-induced nonlinear dynamics in hybrid graphene-based photonic waveguides

TL;DR

This paper presents a theoretical model for infrared pulse propagation in graphene-covered hybrid waveguides, revealing how free carriers induce nonlinear effects such as soliton acceleration and spectral blueshift, supported by numerical and semi-analytical analysis.

Contribution

It introduces a first-principles model combining electron dynamics and nonlinear pulse propagation in graphene-based photonic waveguides, highlighting free-carrier effects on soliton behavior.

Findings

Kerr solitons accelerate due to free carriers

Strong spectral blueshift observed in simulations

Model aligns with semi-analytical predictions

Abstract

We develop from first principles a theoretical model for infrared pulse propagation in graphene-covered hybrid waveguides. We model electron dynamics in graphene by Bloch equations, enabling the derivation of the nonlinear conductivity and of a rate equation accounting for free-carrier generation. Radiation propagation is modeled through a generalized nonlinear Schr\"{o}dinger equation for the field envelope coupled with the rate equation accounting for the generation of free carriers in graphene. Our numerical simulations clearly indicate that unperturbed Kerr solitons accelerate due to the carrier-induced index change and experience a strong self-induced spectral blueshift. Our numerical results are fully explained by semianalytical predictions based on soliton perturbation theory.