Publication Date

8-2012

Type of Culminating Activity

Thesis - Boise State University Access Only

Degree Title

Master of Science in Materials Science and Engineering

Department

Materials Science and Engineering

Major Advisor

Bernard Yurke

Abstract

Because of their unique optical properties, gold nanoparticles have potential applications in the construction of nanoscale optical and photonic devices that operate at length scales below that of the diffraction limit of light. As an aid for the design of such devices, a phenomenological model was proposed and interaction mechanisms between gold nanoparticles, in the presence of an externally applied field, were investigated. A general equation of motion that governs the interaction mechanisms of the system was derived. The general equation of motion takes into account the radiation and intrinsic damping, coupling between induced dipoles and the applied field, and the induced dipole-dipole coupling. The dependence of the damping constants and the coupling parameters on the size of the gold nanoparticle was investigated. The dispersion relations for chirally arranged gold nanoparticles was calculated numerically and analytically. The optical properties of metallic nanoparticles arranged in a chiral structure were also studied. Circular dichroism (CD) and optical rotary dispersion (ORD) were calculated numerically for various numbers of gold nanoparticles. The CD extinction coefficient as a function of wavelength was obtained for a chiral structure with four nanoparticles per turn. The ORD coefficient as a function of wavelength was calculated for chiral structures with four and six nanoparticles per turn. The numerical results have revealed that a chiral structure with six nanoparticles per turn, compared with a structure with four nanoparticles per turn, yields much stronger ORD signals even if it has a smaller number of gold nanoparticles.

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