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

High-Q deformed silica microsphere cavities are fabricated by short CO2 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 107 in these microspheres is achieved, and a transition from two-directional to single-directional emission is observed. Such concentrated directional emission and...