Precision of light scattering techniques for measuring optical parameters of microspheres

Abstract

This experimental and theoretical study of light scattering techniques addresses the questions of deconvolution of light scattering data (phase functions and optical resonance spectra) from droplets and the uniqueness of that deconvolution for the measurement of size and refractive index of microspheres. Theory and experiment are compared for single component and multicomponent microdroplets and for layered microspheres levitated in electrodynamic balances. Size changes of the order of 1 Å have been measured by tracking resonance shifts of slowly evaporating single component droplets. For multicomponent droplet evaporation, which involves simultaneous size and refractive index changes, and for rapid evaporation, precision is reduced to ∼1 part in 10⁴ for each parameter.