Hollow-core resonator based on out-of-plane 2D photonic band-gap crystal cladding

We report on the demonstration of a resonator based on electromagnetic field confinement in a hollow-core by an out-of-plane 2D photonic band-gap (PBG) crystal cladding. The resonator is designed to concentrate the energy within an air region in the center of the resonator and away from the cavity walls to minimize conductor losses. In contrast with in- plane 2D PBG crystal devices, the PBG crystal studied here is perpendicular to the propagation plane. A resonator was constructed with silica rods to prove the concept at frequencies around 30 GHz.