Abstract

Optical cavities are important parts of many scientific and industrial instruments and have been widely studied in the field of optics and photonics. The Surface nanoscale axial photonic (SNAP) cavity, a whispering gallery mode (WGM) type optical cavity has recently gained attention and became the focus of active research. In this thesis we present our work to make a thin-walled hollow SNAP cavity by using a hydrogen torch and a tapered microfiber (TMF) pulling setup. Our method does not require a carbon dioxide laser nor hydrogen fluoride etching. We use a tapered microfiber to excite localized optical resonant modes in the walls of this cavity. We show that when the walls of the capillary are thin enough (10 microns), the electric field from resonance mode extends beyond the internal walls of the cavity and interacts with the medium (air or water) inside the cavity. This shows a proof-of-concept that the thin-walled hollow SNAP cavities can be used as an optical microfluidic sensor. We also measure the transmission impulse response and light pulse dynamics of a SNAP optical cavity using an optical backscatter reflectometer. From the data we compute the lifetime of the light in the SNAP cavity in the time domain, and its round trip time.