Silicon nanocrystal luminescence coupled to whispering gallery modes in optical fibers

Oxide-embedded silicon nanocrystals (Si-NCs) are a promising material for microphotonics, particularly when coupled to high quality factor (Q-factor) optical cavity modes. By glazing smooth nanocrystalline films from a solution-based precursor onto the surface of optical fibers, the Si-NC luminescence can be strongly coupled into the optical modes of the fiber. Well-developed whispering gallery modes occur in the luminescence of the Si-NCs measured perpendicular to the fiber axis, showing detection-limited Q-factors in the emission spectrum. In addition to providing high Q-factor fluorescence without the need for lithographic procedures, the physical versatility of a nanocrystal-coated fiber suggests possible refractometric applications.