Optical bistability in two-dimensional nonlinear composites of coated cylinders with nonlinear core and graded shell

Ya M Wu,Yang Huang,Guo Q Chen,Yi X Wang,Wen C Wu,Yan Shi,Hongyu Shi,Jiafu Wang,Kun Song

doi:10.1051/epjam/2020006

Abstract

The intrinsic optical bistability of the nonlinear composite consisting of coated cylinders with nonlinear core and graded Drude shell is investigated with self-consistent mean-field approximation. We derive the nonlinear equation of near field for such graded composite in the quasistatic limit. We demonstrate that the bistability threshold and the bistable width are highly dependent on the core radius, the incident frequency, and the graded coefficient of the coated cylinder inclusion. It is found that the optical bistability appears only when the core radius and the incident frequency satisfy some specific conditions. Therefore, the optical bistability for nonlinear composite materials may be optimized by the suitable adjustment of the physical and geometrical parameters. Our results may be helpful for the design of the nonlinear device with appropriate bistability.

Highlights

Optical bistability has attracted widespread interests for decades, due to its novel feature of controlling light with light [1,2,3,4,5,6]
For two-component nonlinear composite system, variational methods [7] and self-consistent mean-field approximation [8,9] were developed to investigate the nonlinear response of composite system and to explore optical bistable behavior [7,8,9]
It is well-known that the local field enhancement of composite system may result in the optical bistability, which can be adjusted by controlling the local microstructure and the physical parameters of components in the composite system

Summary

Introduction

Optical bistability has attracted widespread interests for decades, due to its novel feature of controlling light with light [1,2,3,4,5,6]. Effective linear dielectric constant [24], three-order nonlinear susceptibility [25] and two-(three) harmonics generations for the nonlinear susceptibilities [26] of the random granular composites with the graded core-shell structure were paid a lot of attentions. In this connection, Huang et al [27,28] found that the gradient structure allows linear and nonlinear responses of the composite to show a wide plasmonic resonance band, which helps to enhance the effective nonlinear response of the composite. We believe our study may be helpful for the design and preparation of optical bistable materials and relative devices

Theoretical model

Numerical results and discussions

Conclusion