Multiband perfect absorbers using metal-dielectric films with optically dense medium for angle and polarization insensitive operation.

The cavity resonant properties of planar metal-dielectric layered structures with optically dense dielectric media are studied with the aim of realizing omnidirectional and polarization-insensitive operation. The angle-dependent coupling between free-space and cavity modes are revealed to be a key leverage factor in realizing nearly perfect absorbers well-matched to a wide range of incidence angles. We establish comprehensive analyses of the relationship between the structural and optical properties by means of theoretical modeling with numerical simulation results. The presented work is expected to provide a simple and cost-effective solution for light absorption and detection applications that exploit planar metal-dielectric optical devices.