Whispering-gallery-mode resonators for miniature optical clocks

Crystalline whispering gallery mode (WGM) resonators are small and structurally monolithic, yet capable of ultra-high quality factors and dramatically enhanced optical nonlinearities. These properties can be exploited in developing miniature optical clocks. Several studies have explored using WGM resonators as frequency reference cavities, and there also exists great research interest in using WGMs for frequency comb generation. In this paper, we will describe our efforts in pursuing laser stabilization using WGM reference cavities with both passive and active temperature stabilization schemes. We will also present our latest analysis and experimental results in frequency comb generation in WGM resonators.