Strong nonlinear optical response of graphene flakes measured by four-wave mixing

TL;DR

This paper experimentally demonstrates that graphene flakes exhibit a high third-order nonlinear optical response at near-infrared frequencies, enabling enhanced imaging contrast compared to linear microscopy.

Contribution

It provides the first experimental measurement of nonlinear optical properties of graphene flakes, revealing their wavelength-independent high third-order nonlinearity.

Findings

Graphene monolayers show high third-order nonlinearity at near-infrared frequencies.

Nonlinear optical response is nearly wavelength-independent.

Enhanced imaging contrast using nonlinear optical properties of graphene.

Abstract

We present the first experimental investigation of nonlinear optical properties of graphene flakes. We find that at near infrared frequencies a graphene monolayer exhibits a remarkably high third-order optical nonlinearity which is practically independent of the wavelengths of incident light. The nonlinear optical response can be utilized for imaging purposes, with image contrasts of graphene which are orders of magnitude higher than those obtained using linear microscopy.