Second-harmonic generation in subwavelength graphene waveguides

TL;DR

This paper proposes a new method for second-harmonic generation in subwavelength graphene waveguides by using quadratic phase matching enabled through spatial conductivity modulation, supported by theoretical predictions.

Contribution

It introduces a novel approach utilizing spatially modulated conductivity in graphene to achieve phase matching for nonlinear plasmonic interactions.

Findings

Quadratic phase matching can be achieved in double-layer graphene structures.

Graphene's nonlocal conductivity enables second-order nonlinear processes.

Theoretical predictions show potential for efficient second-harmonic generation.

Abstract

We suggest a novel approach for generating second-harmonic radiation in subwavelength graphene waveguides. We demonstrate that quadratic phase matching between the plasmonic guided modes of different symmetries can be achieved in a planar double-layer geometry when conductivity of one of the layers becomes spatially modulated. We predict theoretically that, owing to graphene nonlocal conductivity, the second-order nonlinear processes can be actualized for interacting plasmonic modes with an effective grating coupler to allow external pumping of the structure and output of the radiation at the double frequency.