Manipulating type-I and type-II Dirac polaritons in cavity-embedded honeycomb metasurfaces

TL;DR

This paper theoretically demonstrates how cavity-embedded honeycomb metasurfaces can manipulate type-I and type-II Dirac polaritons by altering the photonic environment, enabling control over their properties without changing the lattice structure.

Contribution

It introduces a novel method to control Dirac polaritons in metasurfaces through cavity modifications, revealing rich Dirac physics without lattice alterations.

Findings

Two distinct species of massless Dirac polaritons identified.

Cavity environment can shift the location of type-II Dirac points.

Manipulation of polariton phases achieved solely via photonic environment.

Abstract

Pseudorelativistic Dirac quasiparticles have emerged in a plethora of artificial graphene systems that mimic the underlying honeycomb symmetry of graphene. However, it is notoriously difficult to manipulate their properties without modifying the lattice structure. Here we theoretically investigate polaritons supported by honeycomb metasurfaces and, despite the trivial nature of the resonant elements, we unveil rich Dirac physics stemming from a non-trivial winding in the light-matter interaction. The metasurfaces simultaneously exhibit two distinct species of massless Dirac polaritons, namely type-I and type-II. By modifying only the photonic environment via an enclosing cavity, one can manipulate the location of the type-II Dirac points, leading to qualitatively different polariton phases. This enables one to alter the fundamental properties of the emergent Dirac polaritons while preserving the lattice structure - a unique scenario which has no analog in real or artificial graphene systems. Exploiting the photonic environment will thus give rise to unexplored Dirac physics at the subwavelength scale.