Local photonic density of states in hyperbolic metasurfaces

Abstract

In this work, we design and study an optical hyperbolic metamaterial of a few layers (i.e. metasurface), with a specific in-plane dispersion relationship that has a transition from open hyperbolic type I to type II. We will show that although there is no longer a topological transition from a closed curve to an open hyperbola in dispersion relationship, the local photonic density of state (PDOS) still can be significantly enhanced around the transition point, due to epsilon-near-zero (ENZ) modes. We also show a finite-size effect, which leads to the PDOS enhancement that is strongly dependent on the top layer of material. It is found a balance between the ENZ modes and surface plasmon polaritons for PDOS enhancement. Our results provide some insights for enhancing light–matter interactions via hyperbolic metasurfaces.