Design of a new photonic/plasmonic microcavity allowing a strong light-matter interaction

We present a novel configuration of photonic/plasmonic microcavity with a 1D photonic crystal cavity (PhC) vertically coupled to a metal slot. A strong light-matter interaction is allowed, due to a strong photons confinement in the metal slot, which corresponds to a low mode volume (V = 2×10^-3 (λ/n)³). A Q-factor of 2.6×10³ has been obtained, providing a ultra-high Q/V = 1.3×10⁶ (λ/n)^-3, with a resonance transmission of 48 % λ = 1563.70 nm. Accurate 3D Finite Element Method (FEM) simulations have been performed to design the cavity. Optical trapping has been identified as the most suitable application for the proposed device, due to a strong gradient of the light field in the metal slot that allows high values of optical force and, consequently, the ability to trap nanoparticle with a diameter less than 100 nm.