Event Details
High Q Whispering Gallery Resonator Sensing
Presenter: Wenyan Yu
Supervisor: Dr. Tao Lu
Date: Mon, August 13, 2012
Time: 14:30:00 - 15:30:00
Place: EOW 430
ABSTRACT
ABSTRACT:
High sensitive biosensor is one of the most important applications of the Whispering Gallery Mode (WGM) cavity. Thanks to its ultra high quality factor Q and small optical mode volume, the resonant frequency shift of a single nanoparticle binding becomes detectable. The basic principles of a WGM cavity and its coupling mechanism with an optical coupler are discussed in detail. From the WGM sensing principle, we demonstrate the positive contribution of the surface plasmon to the sensitivity. Furthermore, we implement the localized surface plasmon resonance (LSPR) on the cavity surface. We use the focused ion beam (FIB) to direct deposit metallic nanodots on the spherical cavity surface for the first time. The quality factor of the cavity with metallic dots is above 10^7 in both air and water, which is more than one order larger than other published results. Besides, the new method is much more controllable and repeatable than previous methods.