Nano-Spectroscopic Imaging of Matter

Interactions at the nanometer length scale in hard and soft condensed matter give rise to intriguing phases in correlated electron materials, lead to the design of exotic metamaterials, and offer enormous opportunities for the development of novel therapeutics and vaccines. I will present my group’s recent study of subwavelength-scale interactions in hard and soft condensed nanomaterials using terahertz, infrared, and optical nanoscopy techniques with diffraction unlimited spatial resolution down to ~15 nm.  I will give a summary of our recent results on the following selected representative topics: i) Using polarization-selective near-field imaging techniques, we simultaneously monitored the interaction of insulator-to-metal transition (IMT) in correlated material VO2 and plasmons on gold infrared nanoantennas. We demonstrated localized dynamic reversible switching of VO2 IMT on the scale of 15 nm or less and control of nanoantennas. ii) We studied nanoscale near-field properties of a-few-atomic-monolayer nanoflakes of black phosphorus that exhibit high surface polarizability consistent with its surface-metallic, plasmonic behavior at mid-infrared frequencies. iii) We used nano-spectroscopic imaging to investigate the chemical and structural modifications that occur prior to membrane fusion in the single archetypal enveloped virus, influenza X31. We traced the nanoscale real-space structural and spectroscopic alterations that occur during environmental pH variations in single virus particles