Infrared nano-imaging and -spectroscopy: methods, applications, and current research
Infrared (IR) vibrational scattering scanning near-field optical microscopy (s-SNOM) has advanced to become a powerful nano-imaging and -spectroscopy technique to probe molecular and lattice vibrations, low-energy electronic excitations and correlations, and related collective surface plasmon, phonon, or other polaritonic resonances. s-SNOM enables the study of complex heterogeneous materials with simultaneous nanoscale spatial resolution and quantum state spectroscopic specificity. It has also been extended to studying dynamics in the time domain, where ultrafast vibrational and electronic spectroscopy unravels mechanisms underlying functionality in quantum materials. I will discuss light sources, implementations of nano-probe spectroscopy and imaging, and open scientific questions that are being addressed with these techniques.