Bistable scattering in graphene-coated dielectric nanowires

TL;DR

This paper investigates optical bistability in graphene-coated dielectric nanowires, demonstrating low switching intensities and identifying relaxation time as a key factor, advancing high-speed all-optical signal processing.

Contribution

It develops a semi-analytical model for bistable scattering in graphene-coated nanowires, highlighting the impact of graphene's relaxation time on switching thresholds.

Findings

Switching intensities can be below 1MW/cm2.

Relaxation time significantly influences bistability.

Guides future high-speed optical signal processing applications.

Abstract

In nonlinear plasmonics, the switching threshold of optical bistability is limited by the weak nonlinear responses from the conventional Kerr dielectric media. Considering the giant nonlinear susceptibility of graphene, here we develop a nonlinear scattering model under the mean field approximation and study the bistable scattering in graphene-coated dielectric nanowires based on the semi-analytical solutions. We find that the switching intensities of bistable scattering can be smaller than 1MW/cm2 at the working frequency. To further decrease the switching intensities, we show that the most important factor that restricts the bistable scattering is the relaxation time of graphene, rather than the chemical potential and the permittivity of the dielectric nanowire. Our work not only reveals some general characteristics of graphene-based bistable scattering, but also provides a guidance to further applications of optical bistability in the high speed all-optical signal processing.