Coupling between subwavelength nano-slits lattice modes and metal-insulator-graphene cavity modes: A semi-analytical model

TL;DR

This paper introduces a semi-analytical model to explain resonance phenomena in a hybrid system of subwavelength slit arrays on insulator/graphene layers, highlighting weak and strong coupling effects.

Contribution

The paper develops a simple semi-analytical model that captures the spectral response of a hybrid nano-structure with coupled plasmonic and lattice modes.

Findings

The model accurately predicts broadband and narrowband spectral features.

Weak coupling causes broadband spectra, strong coupling leads to narrowband spectra.

The approach enables efficient analysis of complex hybrid plasmonic systems.

Abstract

We present a semi-analytical model of the resonance phenomena occurring in a hybrid system made of a 1D array of periodic subwavelength slits deposited on an insulator/graphene layer. We show that the spectral response of this hybrid system can be fully explained by a simple semi-analytical model based on a weak and strong couplings between two elementary sub-systems. The first elementary sub-system consists of a 1D array of periodic subwavelength slits viewed as a homogeneous medium. In this medium lives a metal-insulator-metal lattice mode interacting with surface and cavity plasmon modes. A weak coupling with surface plasmon modes on both faces of the perforated metal film leads to a broadband spectrum while a strong coupling between this first sub-system and a second one made of a graphene-insulator-metal gap leads to a narrow band spectrum. We provide a semi-analytical model based on these two interactions allowing to efficiently access the full spectrum of the hybrid system.