This thesis examines the feasibility of using conventional semiconductors, specifically GaAs, as a plasmonic material at the operating wavelength of 1550nm, due to its many merits such as achievable low losses and mature micro-fabrication technologies. A theoretical study is performed on GaAs that yielded the condition for plasmonic behaviour at a minimum free carrier density of 7.2 x 10^20cm^-3 in bulk materials. The most feasible route to achieving this condition is determined to be intense optical excitation, and the required intensity considering a 150fs pulse at the above bandgap wavelength of 870nm is approximately 2.55TW/cm^2. A Bragg reflection ridge waveguide (BRW) using
GaAs-AlGaAs is designed and micro-fabricated, and a counter-propagating pump-probe experiment is devised to test the plasmonic effect using the BRW. Results from two different ultrafast lasers include the observation of pump (870nm and 800nm) coupling to fundamental Bragg modes, and the measurement of the pump transmission spectrum.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/29646 |
| Date | 29 August 2011 |
| Creators | Wong, Herman Man Kai |
| Contributors | Helmy, Amr S. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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