Polycrystalline diamond thin-film Fabry-Perot optical resonators on silicon

Micro-optical devices have applications ranging from gas detection to optical computing. Michigan State University has the capability to deposit high optical quality diamond thin films on silicon substrates using microwave cavity plasma reactors. Diamond is of interest for optical applications due to its high index of refraction and wide spectral transmission range. Combining polycrystalline diamond thin film deposition techniques and MEMS fabrication techniques, an array of optical wavelength Fabry-Perot resonators on a silicon wafer has been constructed and accurately modeled.; This thesis describes the first fabrication of diamond thin-film Fabry-Perot resonators on silicon wafers. Standard fabrication techniques are employed, including thermal oxidation, photolithography, PECVD diamond deposition, anisotropic wet etching, and sputtering. The optical performance of the resonators is investigated by measuring the through-transmission of the device as a function of wavelength. Performance is correlated with the physical properties of the device, including surface roughness.; Transmission of the device is simulated with multi-layer optics theory. A novel method of incorporating surface roughness into standard multi-layer optics theory is developed in the thesis, and applied to the resonators considering the surface roughness of the diamond film to be modeled by Gaussian and non-Gaussian distributions. The models provide valuable guidance into the design of the resonators.; Atomic Force Microscopy is employed to characterize the surface roughness of the films. The films are found to be approximately Gaussian, but with non-negligible amounts of skewness and kurtosis measured. A Pearson Type-IV distribution is used in the optical simulation to represent non-Gaussian roughness in the diamond film. Use of this distribution improves the fit between theory and experimental measurements.