Nadia A Abdulrahman
Baghdad University, Iraq
Title: Femtosecond laser irradiation for hot spots mapping on the surface of plasmonic nanostructures
Biography
Biography: Nadia A Abdulrahman
Abstract
In this research, we present a novel method for visualising plasmonic `hot spots` upon plasmonic surfaces of gold nanostructures. Here, femtosecond laser pulses have been used to map the locations of localised high intensity electromagnetic fields (the hot spots). Upon irradiation with 800 nm femtosecond laser pulses, which may be linearly or circularly polarised, it is possible to reveal the locations of plasmonic hot spots since the nanostructures are physically damaged i.e. undergo melting by the intense heat generated by femtosecond laser pulse irradiation. SEM microscopy may be used subsequently to map the surface to show which areas have been damaged, and hence reveal where the hot spots are. 2D arrays of quadric units (arranged in a racemic fashion) consisting of two patterns, gammadionsand G-like shapes, have been used as plasmonic chiral nanostructures. It has been found that irradiation with linearly polarised light affected segments that are perpendicular to the polarisation direction of the incident beam. However, irradiation with circularly polarised light affected both horizontal and vertical segments of the nanostructures regardless of the sense of individual features (i.e. left-handed or right-handed) or the sense of the circular polarisation of the incident beam (i.e. clockwise or counter-clockwise). Hence, no enantio-selectivity was observed.