Nanotextured Dynamics of a Light-Induced Phase Transition in VO.

We investigate transient nanotextured heterogeneity in vanadium dioxide (VO) thin films during a light-induced insulator-to-metal transition (IMT). Time-resolved scanning near-field optical microscopy (Tr-SNOM) is used to study VO across a wide parameter space of infrared frequencies, picosecond time scales, and elevated steady-state temperatures with nanoscale spatial resolution. Room temperature, steady-state, phonon enhanced nano-optical contrast reveals preexisting "hidden" disorder.

Analysis of the thickness dependence of metamaterial absorbers at terahertz frequencies.

Metamaterial absorbers typically consist of a metamaterial layer, a dielectric spacer layer, and a metallic ground plane. We have investigated the dependence of the metamaterial absorption maxima on the spacer layer thickness and the reflection coefficient of the metamaterial layer obtained in the absence of the ground plane layer. Specifically, we employ interference theory to obtain an analytical expression for the spacer thickness needed to maximize the absorption at a given frequency.