Waveguide coupled air-slot photonic crystal nanocavity for optomechanics

Abstract

We investigate a structure consisting of two parallel GaAs membranes with an air-slot type photonic crystal nanocavity, which is designed to achieve efficient optomechanical coupling. The structure shows a large theoretical optomechanical coupling factor of ~990 GHz/nm. We designed, fabricated and performed optical characterization of a system consisting of a grating coupler, a photonic crystal waveguide, and a nanocavity (1540 nm). About 2% of the input power is diffracted, guided, coupled to the cavity mode, and detected by a detection system with a microscope objective lens with an NA = 0.65.