Effects of Geometry on Plasmonic Properties of Nanostructures

The role of polarization in light-matter interactions is a subject of study as old as optics itself and is critical to numerous optical devices. Plasmonic metal nanoparticles, which are potential candidates for many applications due to their unique optical properties, have sensitive polarization responses determined by their nanoscale geometry and local environment. Polarization resolved studies of individual metal nanoparticles of different shapes and geometries are reported with an emphasis on the role of chirality. A novel microscopy method for monitoring chirality in single nanoparticles using differential scattering of circular polarizations is reported, complete with a correction method for linear polarization artifacts. This method is demonstrated through the measurement of self-assembled, twisted gold nanorod dimers. The same method is used to characterize racemically assembled dimers of gold dumbbell shaped particles where individual dimers were shown to have chiral responses, despite no ensemble chiral response. Triangular bifrustrum shaped gold nanoparticles are shown to have their scattering response split into non-degenerate, orthogonal, linearly polarized modes as a direct result of them sitting tilted on a substrate. Lithographically prepared curved gold nanostructures are shown to have very strong scattering modulation in response to switching the handedness of incident circular polarizations, yet a detailed investigation shows this modulation is not driven by helical field oscillations as in traditional circular dichroism. Instead planar, trochoid-type field oscillations present in evanescent fields are shown to be responsible for the dramatic response, which opens the door to an entirely new form of dichroism. In summary, we show that metal nanostructures offer a rich platform to study, manipulate, and utilize light polarization.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Natural Sciences

Grantor

Rice University

Year dc:date.issued

2018

Author dc:creator

• Smith, Kyle Warren

Advisor dc:contributor.advisor

• Link, Stephan

• plasmonics
• chirality
• nanoscience

Statement dc:rights

• Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1911/105741

OAI identifier oai:identifier

oai:repository.rice.edu:1911/105741