Towards absolute scattering cross section of nanoparticles and single molecules

Abstract

Elastic scattering signal from optically active molecules below the Rayleigh regime can be detected by probing its absorption band. Within the absorption band, the optical scattering cross section (SCS) of the molecule is a rapidly varying function of light frequency. Knowing the absolute SCS of a single molecule has many applications like learning about the internal molecular levels (orbitals), or identifying molecules or some chemical processes. For this reason, we proposed an experimental scheme for measuring the absolute SCS of nanoparticles and single molecules. We developed a setup for this measurement, from where, currently, we obtained relative SCSs of particles with low extinction. Further improving the setup and samples will lead us towards absolute SCSs of small particles (like single fluorophores) and quantitative description of resonance light scattering.