Structured Light-Matter Interaction: Twisted Photons in Graphene

TL;DR

This paper introduces a numerical framework to study how structured light with orbital angular momentum interacts with graphene, revealing unique nonlinear optical effects like third harmonic generation.

Contribution

The work develops a novel two-step numerical method coupling Dirac and Maxwell's equations to analyze structured light-matter interactions in graphene.

Findings

OAM conservation during harmonic generation is confirmed.

Spatial and frequency characteristics of third harmonic signals are characterized.

Comparison with traditional frequency responses highlights unique features.

Abstract

In this work we present a numerical framework for studying the interaction of structured electromagnetic fields, i.e., light pulses carrying orbital angular momentum (OAM), interacting with a single layer of graphene. Our approach is based on a two-step process, where first the interaction of structured light with matter, modelled by a suitable Dirac equation is solved and then coupled with Maxwell's equations, for studying the properties in both space and frequency domain of the generated nonlinear electromagnetic field. As an example of application of our method we investigate third harmonic generation by an OAM pulse. We check that OAM conservation through harmonic generation is conserved, and we report on both the spatial and frequency features of the third harmonic signal, comparing it with the traditional frequency response for spatially uniform field.