Controllable Optical Negative Refraction and Phase Conjugation in Graphene

TL;DR

This paper demonstrates controllable negative refraction and phase conjugation at optical frequencies using graphene, leveraging its low loss and broadband properties for potential super-resolution imaging applications.

Contribution

It introduces a novel method employing degenerate four-wave mixing in graphene to achieve broadband, low-loss negative refraction and phase conjugation at optical frequencies.

Findings

Successful demonstration of negative refraction in graphene

Broadband operation enabled by graphene's linear bandstructure

Low-loss, efficient phase conjugation achieved

Abstract

The development of optical metamaterials has resulted in the demonstration of remarkable physical properties, including cloaking, optical magnetism, and negative refraction. The latter has attracted particular interest, mainly because of its promise for super-resolution imaging. In recent years, negative refraction has been demonstrated with plasmonic materials and nonlinear discrete elements. However, the widespread use of negative refraction at optical frequencies is limited by high losses and strong dispersion effects, which typically limits operation to narrow frequency bands. Here we use degenerate four-wave mixing (d-4WM) to demonstrate controllable negative refraction at a graphene interface, which acts as a highly efficient phase-conjugating surface. The scheme has very low loss because of the very small thickness of the nonlinear material and it ensures broadband operation due to the linear bandstructure of graphene.