Fano resonance in whispering gallery photonic microcavities

Fano resonances, sometimes behaving like electromagnetic induced transparency (EIT)-like resonances in whispering-gallery-mode (WGM) microcavities are attracting much attention due to the important applications in high-sensitivity biosensing, optical switch, and slow light. In this paper, Fano resonances in several WGM systems are reported, including in a single WGM photonic microcavity and in coupled WGM microcavities. Specifically, in a single WGM microcavity system, Fano or EIT-like resonances in both polydimethylsiloxane (PDMS) coated silica microtoroid and bare silica microtoroid are experimentally investigated. In coupled microcavity system, we report a theoretical study of EIT-like resonance in an array of microcavities indirectly coupled through a parallel waveguides system. Finally, we experimentally investigate the Fano resonance in two microcavities indirectly coupled via a single fiber taper.