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Presenter: Aftab Ahmed
Supervisor: Dr. Reuven Gordon

Date: Fri, May 21, 2010
Time: 14:30:00 - 15:30:00
Place: EOW 430

ABSTRACT

Abstract:

Plasmonic nanorods are widely utilized in a number of applications such as biosensors [1] and the treatment of cancers [2]. They are also used as the building blocks for metamaterials [3]. Past work to understand the resonant properties of nanorods has mainly been computational [4], which lacks physical insight and is also case specific. Recently, scaling laws for nanorod resonances have been proposed [5]; however, that approach neglects the influence of the ends of the nanorods, which can be significant close to the dipolar resonance. For flat ended rods we have already presented a theory that captures phase and amplitude of reflection from ends accurately [6]. Here we propose a theory that captures the influence for rounded ends. The theory is based on a dipole model for the rounded ends, and it shows significant deviation from the linear scaling laws [5]. We have carried out extensive numerical simulations that support the proposed theory. Fig. 1 shows the field distribution, numerically calculated, of the surface plasmon with the spherical boundary at the rod end. Fig. 2 shows the divergence of the resonance wavelength from the previously proposed linear relation to rod length.