Abstract

Whispering gallery resonators (WGRs) are monolithic cavities that guide light by total internal reflection making any high-reflectivity coatings unnecessary. The only restriction in the spectral range covered is given by the transparency window of the material. Its high quality factor (Q-factor) combined with a small mode volume make this resonator type very useful for applications including nonlinear-optical processes like frequency conversion, as the pump threshold decreases with higher Q-factors for the pump and resulting waves.

© 2015 IEEE