Interactions of Gold Plasmons and Vanadium Dioxide

Abstract

The focus of this dissertation is the interaction of gold (Au) plasmonic structures and the phase change material vanadium dioxide (VO2). Vanadium dioxide modifies the local surface plasmon resonance of an Au nanoparticles and the local surface plasmon can also act as a probe of the VO2 optical properties. Heterostructures combining plasmonic and phase-change materials create platforms with tunable optical properties that provide access to a cornucopia of optical-physics phenomena. In this thesis we specifically look at three such phenomena. First, we demonstrate active plasmon-induced transparency via finite-difference time-domain simulations and investigate an experimental realization of the relevant structure that exhibit plasmon-induced transparency. Second, we observe a novel pattern of coexisting metallic and insulating domains in a VO2 single crystal using plasmonic antennas in a scattering scanning near-field optical microscope, and thus show that even single VO2 crystals are not homogeneous. Third, we employ the optical resonance shifts of plasmonic monomers and dimers embedded in VO2 films to probe the kinetics and dynamics of atomic hydrogen diffusion and its effects on the phase transition. In addition, the challenges inherent in fabricating these complex structures are discussed, illuminating the ways in which the choice of thin-film deposition method influence the resulting VO2 material properties. This work demonstrates the versatility of hybrid material platforms that combine the exquisite optical sensitivity of the surface plasmon resonance with the tunable dielectric functions in phase-changing materials to study the kinetics and dynamics of strong correlations, doping interactions, and classical analogs of atomic phenomena in solid-state systems.