Nanoscale THz imaging and spectroscopy at ambient and cryogenic sub 10 K temperatures

Scattering near-field optical microscopy (s-SNOM) is a powerful technique that can provide wavelength independent optical resolution (< 20 nm), by surmounting the diffraction limit in traditional THz imaging. In this presentation, we report on the implementation of near-field THz s-SNOM for the nanoscale characterization of frequency dependent free carrier response in semiconductors and 2D materials. The specifically designed near-field microscope enables measurements at room temperature and at cryogenic temperatures.