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

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 approach 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 distinguishing distinct materials (or distinct species of the same material). Phasor representation of s-SNOM data proves thus to augment this technique's potential for optically investigating surfaces at nanoscale. In our opnnion, thewidespread of such approaches could bring significant added value in applications where identifying and understanding the physicochemical properties of advanced materials and biological samples at nanoscale is important.