Optical Science and Engineering ETDs

Publication Date

Summer 7-29-2025

Abstract

Plasmon on metal nanoparticles can confine and amplify light at the nanoscale. Coupling metallic nanoparticles to films generates strong electric fields within nanogaps, enabling interfacial processes. However, the origin and nature of these processes remain poorly understood. This dissertation investigates physical, chemical, and optomechanical interactions in plasmonic nanocavities. By linking elastic dark-field scattering with inelastic processes such as photoluminescence and surface-enhanced Raman scattering (SERS), we show that optomechanical coupling between nanocavity plasmons and molecular vibrations leads to laser-plasmon detuning-dependent resonance broadening, indicating energy transfer to molecular vibrations. It has also been demonstrated that picometer-level tuning of plasmon resonances in plasmonic nanocavities can be achieved using photothermal effects in polyelectrolyte spacers, enabling dynamic control of optomechanical SERS enhancement, molecular diffusion, and charge transfer plasmons. Also, it has been shown that the high dielectric constant of the polyelectrolytes improves the optical contrast of the single nanoparticles in the near-field infrared imaging.

Degree Name

Optical Science and Engineering

Level of Degree

Doctoral

Department Name

Optical Science and Engineering

First Committee Member (Chair)

Prof. Terefe G. Habteyes

Second Committee Member

Prof. Ganesh Balakrishnan

Third Committee Member

Prof. Francesca Cavallo

Fourth Committee Member

Dr. Stavroula Foteinopoulou

Keywords

plasmonic nanocavity, molecular optomechanics, thermoplasmonics, SERS, polyelectrolytes, layer-by-layer assembly

Document Type

Dissertation

Language

English

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