Titanium Dioxide Whispering Gallery Microcavities

Abstract

Whispering-gallery-mode (WGM) microdisk and microgoblet resonators are fabricated on silicon chips from amorphous TiO2 films prepared using sol–gel synthesis. The resonators exhibit quality factors as high as 105 in both air and water. These TiO2 microresonators offer great opportunities for WGM-based sensing in biological media, nonlinear optics, optical filtering in the visible band, photocatalysis, and dye-sensitized solar cells due to their high quality factors, high refractive index, strong optical nonlinearity, and intrinsic biocompatibility.