Circular Magnetoplasmonic Modes in Gold Nanoparticles

Abstract

The quest for efficient ways of modulating localized surface plasmon\nresonance is one of the frontiers in current research in plasmonics;\nthe use of a magnetic field as a source of modulation is among the\nmost promising candidates for active plasmonics. Here we report the\nobservation of magnetoplasmonic modes on colloidal gold nanoparticles\ndetected by means of magnetic circular dichroism (MCD) spectroscopy\nand provide a model that is able to rationalize and reproduce the\nexperiment with unprecedented qualitative and quantitative accuracy.\nWe believe that the steep slope observed at the plasmon resonance\nin the MCD spectrum can be very efficient in detecting changes in\nthe refractive index of the surrounding medium, and we give a simple\nproof of principle of its possible implementation for magnetoplasmonic\nrefractometric sensing.