Graphene Plasmon Cavities Made with Silicon Carbide

Area of Science:

• Condensed Matter Physics
• Nanophotonics
• Infrared Spectroscopy

Background:

• Plasmonic cavities are crucial for light-matter interactions.
• Graphene exhibits unique plasmonic properties in the infrared range.
• Efficiently exciting graphene plasmons, especially at normal incidence, remains a challenge.

Purpose of the Study:

• To propose and numerically investigate a simple method for creating tunable infrared plasmonic cavities.
• To explore the absorption properties and field distributions of graphene-based resonant structures.
• To demonstrate strong coupling between graphene plasmons and silicon carbide phonon polaritons.

Main Methods:

• Numerical investigation using the finite element method.
• Modeling graphene films suspended over a silicon carbide grating.
• Analysis of absorption spectra and electromagnetic field distributions.

Main Results:

• The structured silicon carbide substrate acts as a perfect reflector within its reststrahlen band, forming a cavity.
• Graphene plasmon standing waves are established, leading to tunable absorption.
• Clear evidence of strong coupling, observed as Rabi splitting, between localized surface phonon polaritons and graphene plasmon cavity modes.

Conclusions:

• A simple and tunable plasmonic cavity in the infrared range can be realized using graphene on a silicon carbide grating.
• Efficient excitation of graphene plasmons at normal incidence is achievable.
• The demonstrated strong coupling opens avenues for cavity quantum electrodynamics studies and applications in infrared spectroscopy.