Quantifying Aerosol Size and Sphericity from Light Scattering Patterns of Gaussian Random Spheres*

Determining the size and shape of an aerosol is important to a range of fields from climate science to biowarfare detection. In this work, we explore using angularly-resolved light scattering to characterize the sphericity and size of aerosol particles. Aerosol particles were modeled using Gaussian Random Spheres. The shape of the particles could be tuned from spherical to highly nonspherical. This was achieved by varying the parameters associated with the height and size of the fluctuations at the surface of a sphere. Once a particle was simulated, light scattering patterns were generated using the Discrete Dipole Approximation (DDA) assuming illumination from a monochromatic plane. The patterns were analyzed for two features: (1) ring-like structures associated with spherical particles and (2) the speckle-like features associated with high nonspherical particles. Using this analysis, we established correlations between a particle's shape and size and its light scattering behavior.