Controlling deformation in a high quality factor silica microsphere toward single directional emission.

High-Q deformed silica microsphere cavities are fabricated by short CO(2) laser pulses, where the deformation is well controlled by adjusting the intensity and number of pulses. Using this method, directional emission from whispering-gallery mode (WGM) with a high quality factor of 10(7) in these microspheres is achieved, and a transition from two-directional to single-directional emission is observed. Such concentrated directional emission and high-Q of WGMs show high potential for future studies of the chaotic ray dynamics in deformed microcavity and cavity quantum electrodynamics and optomechanics.