On Hybrid Plasmonic Waveguides for Integrated Nonlinear Optics

The promise of plasmonics to compress light into sub-wavelength regions holds a potential pathway for nanoscale nonlinear optical devices. However an inherent trade-o? between light con?nement and propagation loss presently limits its use. A new type of plasmonic structure, which combines the best attributes of dielectric and plasmonic waveguides, has been proposed. Recent theoretical studies of these hybrid plasmonic waveguides, along with some experimental results, indicate that these structures can maintain a high ?eld con?nement while reducing propagation loss to moderate levels. Hence, this new structure obtains the best of both platforms and may be key to producing e?cient all optical nonlinear devices. If compact optical data processing is to be achieved via hybrid plasmonic structures, it is necessary to investigate their nonlinear properties and compare them to alternative platforms. Although simulations and theoretical work on hybrid modes for a large range of geometries and structures have been publish, there has been little experimental work investigating its nonlinear properties.In this thesis the candidate experimentally investigates the nonlinear properties of a hybrid plasmonic structure. The proposed structure is based on a silicon nanowire, which allows the use of a bare silicon waveguide as a control sample. The structure geometry is varied slightly in order to measure its e?ect on the nonlinearity, positive results in this regards would indicate that there is room for structure optimization. In order to achieve the experimental results a sensitive method for measuring small nonlinear phase shifts was developed and employed. This method enables the candidate to measure the nonlinear phase shift produced by waveguides of tens of micrometer in length. Further theoretical investigation is carried out regarding the platforms nonlinear properties, such as the physical origin of their strong nonlinear parameter and the limits to their optimization. The work in this thesis adds to the body of knowledge regarding the nonlinear properties for hybrid plasmonic structures from both an experimental and theoretical stand point