Surface optical characterization at nanoscale using phasor representation of data acquired by scattering scanning near-field optical microscopy

Abstract Placed at the junction of laser-scanning and probe-scanning techniques, scattering scanning near-field optical microscopy (s-SNOM) is a promising tool for the optical investigation of surfaces at nanoscale resolution. In this work we expand the current possibilities of representing s-SNOM data by coupling typical s-SNOM results (amplitude and phase images) with the phasor representation method, an extremely powerful tool for complex data analysis. Our results demonstrate that representing s-SNOM data in the phasor space can be very useful for surface characterization of different types of materials and can be successfully used for differentiating different materials types (or different species of the same type). Phasor representation of s-SNOM data proves thus to be a reliable tool for nanoscale optical investigations of surfaces, and its widespread could potentially bring significant added value in applications where identifying and understanding the physicochemical properties of advanced materials and biological samples at nanoscale is important.