Novel Optical Devices Based On Whispering-gallery Mode Microcarities

The whispering-gallery mode microcavities have been extensively researched. The WGM microcavities possess ultra-high quality factor and small mode volume and other characteristics. So they have important applications in the new field of optics for low-threshold lasers, narrow-band filters and high-sensitivity sensors.This paper aims to carry out some theoretical and experimental explorations on WGM microcavity-based optical devices. The basic optical properties of microresonators are firstly described, and WGM mode distributions of micro-cylinder and micro-ring resonators are analysed, and the research is especially focused on the influence factors on resonances. Then a detailed description is provided concerning the fiber taper characteristics about transmitting light by local mode theory. The theoretical model of fabricating optical fiber is presented according to mass conservation. And the low loss fiber taper is successfully prepared in experiment. In addition, brief theory researches will be carried out on the basic model of the microcavity coupling system, mainly on the system Q-factor and the phase matching problem. This paper proposes a novel tunable optical filter based on the slowly varying cylindrical microcavity. The tunable scheme is based on the dependence of resonance on microcavity morphology. The scheme is carried out in experiment to verify the feasibility of the program, and wide range tuning is observed. The paper also studies the microcapillary-based biochemical sensors, and systematically analyses the working mechanism and characteristics parameters of the sensors. Optimization programs concerning higher sensitivity and lower thermal noise are proposed. The4th-order WGM is picked out in experimental data and it shows significantly advantage in sensing sensitivity.