Optical nonlinearity enhancement of graded metal-dielectric composite films

TL;DR

This paper analytically derives the local electric field in graded metal-dielectric films, showing how composition gradation enhances optical nonlinearity and creates broad resonant plasmon bands for improved optical applications.

Contribution

It introduces an analytical method to evaluate local electric fields and nonlinear susceptibilities in graded composite films, revealing the impact of gradation on optical nonlinearity enhancement.

Findings

Gradation induces broad resonant plasmon bands in the optical region.

Enhanced third-order nonlinear susceptibility due to composition-dependent gradation.

Potential for improved optical device performance through graded structures.

Abstract

We have derived the local electric field inside graded metal-dielectric composite films with weak nonlinearity analytically, which further yields the effective linear dielectric constant and third-order nonlinear susceptibility of the graded structures. As a result, the composition-dependent gradation can produce a broad resonant plasmon band in the optical region, resulting in a large enhancement of the optical nonlinearity and hence a large figure of merit.