Local photonic density of states in hyperbolic metasurfaces

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.

Automated summary

In this work, we designed and studied an optical hyperbolic metasurface with a specific in-plane dispersion relationship transitioning from type I to type II. Although there is no longer a topological transition in the dispersion relationship, the PDOS can still be significantly enhanced around the transition point due to ENZ modes. The enhancement of PDOS is found to depend strongly on the top layer of material, with a balance between ENZ modes and surface plasmon polaritons.