A Study On Two-mode Couplings In Sausagelike Microresonators

Whispering-gallery-mode(WGM)optical microresonator is an optical device to enhance the interaction between light and matter,usually has a high quality factor.In this thesis,the WGM microresonator involved are the sausage-like microresonator and microsphere.One of the advantages of the sausage-like microresonator is that the WGM resonance wavelength can be tuned by simply stretching its cavity length.This thesis studies the coupling phenomenon of two WGMs theoretically and experimentally,and the specific contents include experimentally studying the two-mode coupling phenomenon in one single sausage-like microresonator,theoretically exploring the two-mode coupling phenomenon in two WGM microresonators,and experimentally studying the two-mode coupling phenomenon in the coupled system consisting of a sausage-like microresonator and a microsphere.In the experimental study of the two-mode coupling phenomenon in one single sausage-like microresonator,we observed the Fano-like phenomenon,the electromagnetically induced transparency phenomenon and the electromagnetically induced absorption phenomenon by stretching the sausage-like microresonator to change the difference of the resonance wavelength between two optical modes.In the theoretical study of two-mode coupling phenomenon in two WGM microresonators,we studied the relationship between the transmission spectrum and the coupling strength between the two modes,the coupling loss of the first microcavity mode,and the loss of the second microcavity mode,respectively,where the resonance wavelengths of the two microcavity modes are equal.In the experimental study of the two-mode coupling phenomenon in the coupled system consisting of a sausage-like microresonator and a microsphere,where there is a coupling between the fiber taper and the sausage-like microresonator,and there is also a coupling between the microsphere and the sausage-like microresonator,but there is no coupling between the microsphere and the fiber taper.We experimentally studied the effect of the difference between the resonance wavelengths of the sausage-like microresonator mode and the microsphere mode on the transmission spectrum,and experimentally studied the effect of the gap between the microsphere and the sausage-like microresonator,the gap between the fiber taper and the sausage-like microresonator on the transmission spectrum when the resonance wavelengths of the sausage-like microresonator mode and the microsphere mode are equal.