Hybrid dielectric slot-plasmonic ring resonator for Purcell enhancement

We present a computational study of Purcell factor enhancement for a novel hybrid-plasmonic ring resonator using a novel implementation of the body-of-revolution (BOR) finite-difference time-domain (FDTD) method. In this hybrid structure, a dielectric slot ring is surrounded by a metallic ring such that a hybrid plasmonic mode is generated within two thin low-index gaps. The surrounding metallic ring decreases the binding loss for small ring radii, leading to high-quality factors and mode-field confinement. The hybrid resonator shows high quality-factor values above 103 and small mode volumes down to 10-3(lambda/n)(3) simultaneously, thus providing large Purcell factors (F p > 10(4)). The distributed strong confinement within two gaps renders the proposed resonator useful for multi-emitter applications.