The Surface Plasmon Of The Metal Coated Microcylinder Cavity

The conventional dielectric structure used as a resonator provides a very effective tool for a lot of photonic applications, such as data communications, high-sensitivity biological & chemical sensors and low threshold lasers. In the same time, it is also used for fundamental studies, like cavity optomechanics, cavity quantum electrodynamics and so on. On the other hand, the metal-dielectric structure cavity is also been studied because of the electron density wave excited in the interface between metal and dielectric materials called Surface Plasmon Polaritons (SPPs). It has a tight confinement of the optical field as well as a strong enhancement of the optical field of the resonance in the metal interface which makes it very suitable for the application mentioned above. But the huge loss of the Surface Plasmon Polaritons limits its applications.We research and demonstrate a new kind of microcavity called metal-coated microcylinder cavity in this thesis. It is fabricated by coating a very thin metal film on the surface of the ordinary single-mode fiber which is firstly immersed into the solution of hydrofluoric acid to reduce the radius of the fiber to a certain value. The light couples into the microcavity and propagates along the interface of the dielectric material and the metal film. By the prism coupling method, the Surface Plasmon Polaritons (SPPs) modes and the hybrid modes of SPPs and Whispering Gallery Modes (we call it hybrid SPP-WGMs for short) can be excited at the same experiment. We mainly discuss about the dispersion relation of the metal-coated microcavity, as well as the relationship between the quality factor(Q factor) of the resonance modes and the radius of the metal-coated microcavity in this paper. Finally the excitation experiment is conducted by using the prism to couple the light into the metal-coated microcavity. The SPPs modes in this kind of waveguide have a relatively high Q-factor (more than hundreds) and an ultra-high refractive sensitivity (as high as thousands of nm/RIU) because of the tight confinement the optical field in the interface metal film.