Plasmonic nanostructures and metamaterials for nanoscale light-matter interaction

Abstract

The objective of this dissertation is to study the light-matter interaction phenamena at nanoscale in the presence of plasmonic nanostructures and metamaterials. Using the principles of nano-optics, a range of plasmonic nanodevices are developped for molecular sensing, nonlinear optics and surface plasmon lasing. This theoretical and experimental investigation is further extended by studying the effect of plasmon tunneling in sub-nanometer distances and light-matter interaction in atomically thin semiconductors adjacent to plasmonic nanostructures. More specifically, chemically synthesized plasmonic nanocube dimers and chains are studied for ultrasensitive molecular sensing using the wavelength shift of their localized surface plasmon resonance. The effect of interparticle spacing and relative orientation of the nanocubes in the nanocube chains has also been analyzed. The band-edge lattice plasmon waves in plasmonic nanoantenna arrays have been studied and utilized for surface-enhanced Raman spectroscopy. Superchiral spectroscopy at the molecular level is demonstrated using a novel three-dimensional chiral metamaterial. Furthermore, surface-enhanced second harmonic generation in coupled plasmonic nanostructures that support sharp Fano-type resonance features, is studied theoretically and experimentally. Finally, a plasmonic nanolaser incorporating a plasmonic nanocavity and a monolayer of transition metal dichalcogenide is developed.