Deep-subwavelength plasmonic-photonic hybrid band gap opening by acoustic Lamb waves

Abstract

In this letter, the efficient generation of tunable optical band gaps with the help of acousto-optic (AO) interactions in the deep subwavelength regime is proposed. The optical system consists of a thin dielectric slab and a metal surface separated by a nanoscale air gap. This structure allowed for the confinement of hybridized plasmonic-photonic gap modes, which are highly guided within the air gap. The enhanced AO interaction originated from the disturbance of the acoustic Lamb waves of the slab that can strongly boost the AO interface effect and scatter the optical fields. Therefore, wide optical band gaps and forbidden transmissions were observed in hybrid gap modes at telecommunication wavelengths.