Nanoparticle sizing with a resolution beyond the diffraction limit using UV light scattering spectroscopy

We investigated the detection of dielectric nanoparticles using static light scattering spectroscopy (LSS) in the UV range (from 250 to 390 nm). The light scattered by the polystyrene nanospheres in the backward direction were collected by means of an optical fiber probe and a charge-coupled device (CCD) spectrograph. The size distributions of the nanoparticles were obtained by a discrete inverse on the backscattering spectra using a theoretical model based on Mie theory. Our results show that UV LSS can be used to measure the sizes of nanoparticles with an accuracy far exceeding the diffraction limit and to study subwavelength structures at nanometer scale. This technique may find potential scientific and industrial applications including the study of macromolecular complexes at nanoscale, detection and identification of viral particles, non-invasive probing of nanoscale surface structures, and monitoring the processing of pharmaceutical nanoparticles.