Hybrid Photonic−Plasmonic Crystal Nanocavities

Abstract

We propose a hybrid optical nanocavity consisting of photonic crystals coupled to a metal surface with a nanoscale air gap between. The hybridization of photonic crystal modes and surface plasmons across the gap forms hybrid cavity modes, which are highly confined in the low-loss air gap region. Deep subwavelength mode volume and high quality factor are demonstrated at telecommunication wavelength, resulting in an extremely large Q/V_m ratio of 60 000 λ⁻³. This new type of high-Q/V_m broad-band hybrid nanocavity opens up opportunities for various applications in enhanced light−matter interactions.