Nanoscale Electrodynamics of Strongly Correlated Electron Materials

Over the past decade, optical near-field techniques, especially the scattering-type scanning near-field optical microscope (s-SNOM), have undergone tremendous development. This is partly due to the ever-increasing demand for the exploration of the nano-world and partly due to the many technical advances in laser and scanning probe technologies. I will use this opportunity to report the recent advances in the IR and THz near-field microscopy and spectroscopy technology and discuss their applications in the nanoscale electrodynamics in strongly correlated electron materials. Specifically, I will discuss the details of modeling scanning near-field infrared microscopy and its application in understanding the mesoscopic insulator to metal phase transitions in VO2 and Ca2RuO4 with over a broad spectral range (350 cm-1 to 2500 cm-1). I will also discuss the future development of near-field scanning microscope including the cryogenic capabilities and its coupling to ultrafast pump-probe spectroscopy including both IR and THz frequency range. These new developments set the stage for future spectroscopic investigations to access the fundamental properties of complex materials at the nanoscale.