A microcavity laser based on the gain only in the evanescent field region of whispering gallery modes has been demonstrated. A cylindrical microcavity of 125 microm diam was surrounded by rhodamine 6G dye molecules in an ethanol solution of lower refractive index such that whispering gallery modes of the microcavity underwent laser oscillation when the dye molecules in the evanescent field region outside the cavity were excited by a second harmonic of a Nd:YAG laser. For particular pumping spots, single-mode laser oscillation of a transverse magnetic mode was observed at about 600 nm with associated cavity Q of 3x10(7).

Cavity-Q-driven spectral shift of lasing was observed in a cylindrical microcavity formed by rhodamine6G-doped quinoline in a capillary. The envelope of lasing spectrum showed a blueshift induced by the decreasing cavity Q of whispering gallery modes as the pump fluence increases. The thermally induced refractive index changes were measured from the shifts of individual lasing modes. The observed cavity-Q-driven spectral shift was well described by a simple dye laser model, which accounts for the dependence of cavity Q on the thermally induced refractive index change.

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This paper describes a novel atom-cavity interaction induced by periodically poled atom-cavity coupling constant which leads to multiple narrow photoemission bands for an initially inverted two-level atom under the strong coupling condition. The emission bandpass narrowing has a close analogy with the folded Solc filter in the context of quasi-phase matching by periodic poling. We present a closed form solution of the emission probability at the end of interaction and deduce the multiple phase matching condition for this system which is programmable by the interaction time. The Bloch sphere analysis provides a clear understanding of the underlying atomic dynamics associated with the multiple resonances in the semiclassical limit. Furthermore, we show that this interaction can be applied to generation of nonclassical fields with sub-Poisson photon statistics.

We investigate effects of inhomogeneous broadening of excitons on normal mode oscillation in semiconductor microcavities using a coupled oscillator model. We show that inhomogeneous broadening can drastically alter the coherent oscillatory energy exchange process even in regimes where normal mode splitting remains nearly unchanged. The depth, frequency, and phase of normal mode oscillations of excitons at a given energy within the inhomogeneous distribution depend strongly on the energy separation between the exciton and the normal mode resonance. In addition, for an inhomogeneous broadened system, pronounced oscillations in the intensity of the optical field or the total induced optical polarization no longer imply a similar oscillatory coherent energy exchange between excitons and cavity photons.