We propose and demonstrate a thin Au stripe on a truncated 1D dielectric photonic crystal covered with Cytop as a waveguide for Bloch long-range surface plasmon polaritons. High-quality mode outputs were observed and a mode power attenuation of 12–17 dB/mm measured at λ0 = 1310 nm for propagation in the plane of the truncated photonic crystal and within its stopband. The truncated 1D photonic crystal advantageously enables the use of a large range of materials for the substrate, breaking free from the constraint of material symmetry to support long-range plasmons. An input grating coupler implemented as a periodic array of nanoscale Au ridges on a Au stripe was used to excite the mode via perpendicularly incident p-polarized light. The output was provided by adding a second grating coupler near the end of a waveguide to diffract light upward or by polishing the output facet and allowing the mode to radiate into a free-space beam. Advantageously, grating coupling eliminates the need for high-quality end facets, and optical alignment is simplified. Given its practicality, the structure proposed is of strong interest for biosensing.

This thesis documents the micro-fabrication of a Long Range Surface Plasmon Polariton (LRSPP) biosensor device design that incorporates Bragg grating waveguides. The majority of the work involved the fine tuning of the bi-layer lithography, ultraviolet (UV) exposure and metal deposition micro-fabrication procedures. The goal was to resolve very fine features, accurately produce thin metallization and achieve a high quality metal surface. Repeatable resolution of Bragg gratings having a step-in-width from 8μm to 2μm, a 50% duty cycle and a period of 1690nm to 1800nm, was achieved with bi-layer lithography and UV exposure. A gold thickness of 35nm±5% and surface roughness of better than 2nm rms and average was achieved using thermal vacuum chamber deposition. The fabrication was performed on two different substrates; Cytop and a prefabricated Ta 2 O 5 /SiO 2 multilayer stack. iii Acknowledgments I would like to thank my thesis supervisors Dr. Niall Tait and Dr. Pierre Berini for the opportunity to contribute to the optical biosensor project, a fascinating introduction to the field of micro-fabrication, and for their consultation and direction. Very much appreciation extended to my project colleagues, Sa'ad Hassan who acted as a close mentor for much of the project, and Norm Fong and Wei Ru Wong for much consultation. I would like to particularly thank the staff of the Carleton micro-fabrication facilities, Angela McCormick, Rob Vandusen, and Rick Adams for their training, assistance and consultation on the fabrication techniques, and with equipment operation. Appreciation also to personnel at the University of Ottawa opto-electronic facilities, Ewa Lisicka and Anthony Olivieri, for time spent assisting with equipment usage and a special note of thanks to my wife Angela for copy editing.

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We introduce a helium ion beam lithography and liftoff process to fabricate arbitrary nanostructures. Exploiting existing high-resolution positive tone resists such as poly (methyl methacrylate) (PMMA), the process offers three significant advantages over electron beam lithography: (a) the exposing helium ion beam produces a high secondary electron yield leading to fast patterning, (b) proximity effects are negligible due to the low count of backscattered helium ions from the substrate, and (c) the process is transferrable with minimal alteration among different types of substrates (e.g. silicon, fused silica). The process can be used to pattern any material compatible with liftoff such as evaporated metals or dielectrics, and allows overlay of nanostructures precision-aligned to microstructures realised beforehand on the same substrate. The process is demonstrated for several PMMA thicknesses to liftoff different thicknesses of deposited material. Resolution trials are conducted to determine the limits of the process for each PMMA thickness. Isolated lines as narrow as 14 nm, and line-space gratings of 40 nm pitch (50% duty cycle), are produced as resolution tests by lifting off a 20 nm thick Au film. Nanostructures of aspect ratio up to ∼3:1 have been realised. Plasmonic nanoantenna arrays overlaid to microscale contacts are produced as device demonstrators, for which optical measurements are in excellent agreement with theory.

Plasmonic catalysis holds promise for opening new reaction pathways inaccessible thermally or for improving the efficiency of chemical processes. We report a gold stripe waveguide along which infrared (λ 0 ~ 1350 nanometers) surface plasmon polaritons (SPPs) propagate, operating simultaneously as an electrochemical working electrode. Cyclic voltammograms obtained under SPP excitation enable oxidative processes involving energetic holes to be investigated separately from reductive processes involving energetic electrons. Under SPP excitation, redox currents increase by 10×, redox potentials decrease by ~2× and split in correlation with photon energy, and the charge transfer resistance drops by ~2× as measured using electrochemical impedance spectroscopy. The temperature of the working electrode was monitored in situ, ruling out thermal effects. Chronoamperometry measurements with SPPs modulated at 600 hertz yield a commensurately modulated current response, ruling out thermally enhanced mass transport. Our observations indicate opening of optically controlled nonequilibrium redox channels associated with energetic carrier transfer to the redox species.