Date of Graduation

8-2012

Document Type

Thesis

Degree Name

Master of Science in Microelectronics-Photonics (MS)

Degree Level

Graduate

Department

Graduate School

Advisor

Donald K. Roper

Committee Member

Omar Manasreh

Second Committee Member

Julio Gea-Banacloche

Third Committee Member

Kenneth Vickers

Keywords

Applied sciences; Coupled dipole approximatio; Diffraction; Mie theory; Nanostructured arrays; Plasmonics; Polarizability

Abstract

Plasmonic nanoparticles organized in arrays interact to create spectral patterns which are amplified by individual particle polarizability. It was hypothesized that particle polarizability could be used as a predictor of spectral behavior from far-field interactions within the array. Inter-particle coupling produced an extraordinary peak in extinction efficiency at wavelengths equal to or larger than the single particle plasmon resonance peak. Interactions that produced constructive coupling were found to mimic changes in the particle polarizability model. Testing of the hypothesis was performed using the coupled dipole approximation with parametric characterization of array geometries, giving specific particle size and lattice constant combinations which constructively couple diffracted light to individual particle polarizability. An extension to the dipole polarizability in the coupled dipole approximation that included effects from quadrupoles is given here which gave results in support of the hypothesis. Optimization of ordered nanoparticle array configuration through identification of specific polarizability values that yielded constructive coupling has application in enhancement of photovoltaics, sensors, detectors, and other opto-electronic devices.

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