Energy transfer and molecule-radiation interaction in optical microcavities

Laser energy transfer and molecule-radiation interaction in optical microcavity devices are characterized. The device is operated at whispering-gallery modes, and consists of a microcavity and a micro-waveguide coupled by a sub-micrometer air-gap. Emphases are placed on the influences of microcavity size and waveguide compatibility on the energy transfer and storage capability, on the interactions of foreign molecules with the evanescent radiation field surrounding a resonant microcavity. An optimal gap is found for the considered device configuration where maximum energy storage is achieved. This optimal gap is dependent on the resonance mode as well as the morphology. The Q factor increases exponentially with increasing gap and saturates as the gap approaches the optical wavelength. The influence of molecules attachment is demonstrated and the potential in molecular detection is discussed.