Nonlinear optics of graphene and other 2D materials in layered structures

TL;DR

This paper develops a theoretical framework to analyze the nonlinear optical responses of graphene and other 2D materials within layered structures, accounting for environmental effects and enabling precise extraction of nonlinear coefficients.

Contribution

It introduces a comprehensive method to calculate effective electric fields and sheet currents in 2D materials considering layered environments, advancing the understanding of nonlinear optics in these systems.

Findings

Provides a strict extraction method for nonlinear coefficients.

Analyzes the influence of layered structures on nonlinear signals.

Applies the framework to experimental setups for various nonlinear processes.

Abstract

We present a theoretical framework for nonlinear optics of graphene and other 2D materials in layered structures. We derive a key equation to find the effective electric field and the sheet current density in the 2D material for given incident light beams. Our approach takes into account the effect of the surrounding environment and characterizes its contribution as a structure factor. We apply our approach to two experimental setups, and discuss the structure factors for several nonlinear optical processes including second harmonic generation, third harmonic generation, and parametric frequency conversion. Our systematic study gives a strict extraction method for the nonlinear coefficients, and provides new insights in how layered structures influence the nonlinear signal observed from 2D materials.