LIGHT TRAPPING BY ARBITRARILY THIN CAVITIES

Abstract

Simple plasmonic multilayers are found to perfectly trap electromagnetic waves around specific incidence directions, regardless of the sample thickness. Such a counterintuitive feature is acquired via increasing un boundedly the effective path length of the ray into the film with proper tilt of the optical axis. The obtained optimal setups support wide-band operation while being substantially robust with respect to fabrication defects. Accordingly, the reported designs may exceptionally serve a range of objectives, from photovoltaic conversion and sensing to light modulation and detection, as parts of photonic devices requiring high efficiency combined with compact packaging.