Optical Whispering-Gallery Microresonators

Presented by Albert Rosenberger, Oklahoma State University

Dielectric microresonators have extremely sharp optical resonances known as whispering-gallery modes (WGMs). Light traveling down a tapered optical fiber tangent to the equator of a sub-millimeter silica microsphere can couple into a WGM, where it propagates many thousands of times around the sphere by total internal reflection. The evanescent component of a WGM permits interaction of such a mode with matter in the ambient or on the sphere's surface. This enables, for example, intracavity chemical sensing and the construction of ultralow-threshold quantum-dot lasers. I will describe the properties of these WGM microresonators and several applications developed in my group, including microsensors, microlasers, and coupled-resonator-induced transparency.