Photons confined in hollow microspheres

Incorporation of CdSe quantum dots into a thin (<1 mum) surface shell of polymer microspheres (R similar to2-4 mum) is achieved. The room-temperature emission spectra of single, hollow microcavities show several, spectrally well-separated cavity modes in the red-orange spectral range which have been assigned to high-Q whispering gallery modes (WGM) with radial quantum number n=1 and high angular quantum number l. An enhancement of the cavity finesse Q by a factor of about 10 with respect to CdSe-doped bulk polymer microspheres is found. (C) 2001 American Institute of Physics.