s-SNOM for Addressing Optical Phenomena in 2D Materials at Nanoscale

The combination of the atomic force microscopy with optical channels breaks the diffraction limitation for the spatial resolution, enabling optical analysis at nanoscale. Scattering-type near-field optical microscopy employs a tiny metallic probe with typical size of ~10-20 nm to interact with the underlying matter via far-field light confinement. One of the direct applications of the technology enables direct electric field sensing, resolved in both amplitude (intensity) and phase (field direction). That paves the way to the set of approaches, suitable for 2D materials characterization. s-SNOM can be used to detect light propagation at the interfaces, including propagating or localized polaritons. Furthermore, polariton interferometry is a great method for measuring dispersion of 2D materials. Employment of fs-pulsed light sources allows tracking of ultrafast event such as charge-carrier dissipation or relaxation processes in matter. Combination of various approaches providing reflectivity, absorption and photoluminescence and i.e. electric modes (KPFM, c-AFM, etc.) enables correlation nanoscopy, delivering wide picture of the phenomena at nanoscale.<br/>In this talk, I will be introducing the basics of the technology and will highlight typical examples of applications, recent trends and developments.