Hybrid photonic-plasmonic molecule based on metal/Si disks

Abstract

Optical properties of two identical coupled disks forming a “hybrid photonic-plasmonic molecule” are investigated. Each disk is a metal-dielectric structure supporting hybrid plasmonic-photonic whispering-gallery (WG) modes. The WG modes of a molecule split into two groups of nearly-degenerate modes, i.e., bonding and anti-bonding modes. The oscillation of quality factor (Q) with the inter-disk gap d and significant enhancement at certain inter-disk gaps can be observed. An enhanced Q factor of 1821 for a hybrid photonic-plasmonic molecule composed of two 1.2 μm-diameter disks, compared with that for a single disk, is achieved. The corresponding Purcell factor is 191, making the hybrid photonic-plasmonic molecule an optimal choice for subwavelength-scale device miniaturization and light-matter interactions. Moreover, the far-field emission pattern of the hybrid photonic-plasmonic molecule exhibits an enhanced directional light output by tuning the azimuthal mode number for both bonding and anti-bonding modes.

Publication
Optical Express