Silicon nanocrystal photoluminescence in cylindrical whispering gallery resonators

We present photoluminescence studies of Silicon-nanocrystal (Si-NC) coated cylindrycal microcavities. The coatings were prepared by dip-coating standard optical fibers with a solution-based precursor followed by a high-temperature annealing step. The photoluminescence spectra measured perpendicular to the fiber axis show high Q-factor ($\sim$2500) whispering gallery modes, and allows distinction between TE and TM modes. We also show a proof-of-principle implementation of a far-field refractometric sensor using a nanocrystal-coated fiber.