Frequency stabilisation and sensing applications based on whispering-gallery-mode-resonator

This thesis presents the development of high-precision sensors and frequency references based on optical whispering-gallery­-mode-resonators. By measuring the difference between the frequencies of two optical modes, we developed a thermometer of unprecedented temperature resolution. We used this to improve the frequency stability of the resonator. In calcium fluoride resonators we observed self-oscillatory behavior, which was analyzed theoretically ,and then suppressed by a self-therma l­-locking technique. We also demonstrated a triple-mode technique for refractometry and performed proof-of-concept experiment to suppress thermal noise and to improve detection limit. The thesis also examines electromagnetic coupling between orthogonally polarized modes and provides a theoretical explanation.