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Thursday, April 23rd
3:00 PM
36-428
Plasmonics: Sculpting the Flow of Light at the Nanoscale Yields Metamaterials and Devices
Prof. Harry Atwater, California Institute of Technology
ABSTRACT
Plasmonics is a rapidly emerging photonics discipline that enables unusual dispersion engineering and mode localization, and which is having an impact in the development of metamaterials and active nanophotonic devices. Dispersion control and active materials integration have yielded plasmonic components, including i) three- dimensional single layer plasmonic metamaterials ii) all-optical, electro-optic and field effect modulation of plasmon propagation iii) plasmon-enhanced absorption in photovoltaics. Starting from previous work on two-dimensional negative index structures at visible frequencies, we develop a general approach to realization of three- dimensional single-layer, all-angle, polarization-independent negative index metamaterials. Full wave simulations and dispersion calculations of phase and power flow demonstrate that metal-dielectric- metal plasmonic structures are characterized by negative wave vectors and negative refractive indices. Metal-dielectric plasmon waveguides can serve as active switching elements when the dielectric refractive index can be actively modulated. We demonstrate electro-optic refractive index modulation in metal-dielectric-metal plasmon waveguides using low-voltage electro-optic modulation of a silicon field effect channel. The efficiency and cost effectiveness of photovoltaic cells can both be increased by reduction of the active semiconductor absorber layer volume, and fabrication of solar cells with ultrathin absorber volumes opens up new possibilities for photovoltaic device design. |
