Plasmon-assisted Nonlinearity in Atomically Thin Heterostructures Enables Reconfigurable Optics

Plasmons, oscillations of electrons at material interfaces, offer a promising pathway to manipulate light at the nanoscale, but achieving strong nonlinear optical effects typically suffers from energy loss. Line Jelver and Joel D. Cox, both from the University of Southern Denmark, demonstrate that these losses can be overcome in atomically thin materials, revealing a pathway to efficient nonlinear light manipulation. Their research establishes that nonlocal effects, previously considered detrimental, actually mediate strong plasmon-assisted nonlinearity in electrically reconfigurable two-dimensional heterostructures. By modelling phosphorene nanoribbon dimers, the team reveals how precise control of geometry and electrical properties enables tuning of plasmon interactions and selective enhancement of specific harmonic processes, establishing these heterostructures as a versatile platform for advanced nonlinear nanophotonics.

Nonlocal Nonlinear Plasmons in 2D Heterostructures

Plasmons in atomically thin materials offer a compelling route to trigger nonlinear light-matter interactions through extreme optical confinement. This research investigates nonlocal and nonlinear plasmonics within atomically thin heterostructures, exploring phenomena arising from the interplay between light and matter at the nanoscale. Theoretical modelling and numerical simulations reveal that nonlocal effects, stemming from the finite spatial extent of the electron gas, significantly modify plasmon dispersion and field enhancement. The inclusion of nonlinear optical responses, such as third-order susceptibility, introduces functionalities including harmonic generation and optical limiting, enhanced by strong field confinement. These findings demonstrate the potential of atomically thin heterostructures for developing novel nanophotonic devices with enhanced nonlinear performance and tailored optical properties.

This research demonstrates that nonlocal effects mediate strong plasmon-assisted optical nonlinearity in electrically reconfigurable two-dimensional heterostructures. Atomistic simulations capture quantum finite-size and nonlocal effects in the nonlinear plasmonic response of graphene and phosphorene nanoribbon dimers, revealing how symmetry and inter-ribbon coupling shape harmonic generation processes. Independent tuning of geometry and carrier density in nanoribbon heterostructures induces inter-ribbon plasmon hybridization.

Graphene and Phosphorene Nonlinear Optical Properties

This document provides supporting data for research focused on the nonlinear optical properties of graphene and phosphorene nanoribbons. It includes computational details, validation of computational methods, detailed results supporting claims made in the main paper, and analysis of combined graphene and phosphorene structures. Tables and figures detail computational parameters, electronic band structures, and linear extinction spectra of heterostructures, demonstrating the tunability of optical responses and switching behavior.

Heterostructure Geometry Dictates Nonlinear Optical Control

This research demonstrates significant control over nonlinear optical responses in atomically thin materials, specifically graphene and phosphorene nanoribbon heterostructures. By carefully engineering the geometry and doping of these heterostructures, scientists have revealed how to manipulate plasmon-driven light-matter interactions, achieving enhanced second and third-order nonlinearities at the nanoscale. Vertically stacked configurations promote stronger second-order effects due to enhanced plasmonic mode hybridization, while coplanar geometries tend to optimize third-harmonic generation. Both passive symmetry breaking, through structural design, and active tuning via charge carrier doping can be used to control these nonlinear processes, allowing for selective enhancement of specific harmonic orders. The findings indicate that optimized mode matching and careful doping selection can significantly enhance nonlinear absorption coefficients, suggesting potential applications in efficient two-photon absorption.