Polarized light illuminated scattering characteristics of single airborne particle

Abstract

We demonstrate a method of classifying aerosol particles with different shapes based on the two separated vertical and horizontal polarized beams spaced by 90-100 µm. Model 3321 Aerodynamic Particle Sizer Spectrometer (APS3321) was used to set up an experimental apparatus to test aerosol samples of different shapes, such as spherical oleic acid droplets and elongated crystallized riboflavin. The receiver operating characteristic (ROC) curve was applied to analyze the discrimination ability of the difference in light-scattering intensity to samples with different shapes in the different particle size ranges. The results show that under our experimental conditions, for spherical particles and elongated particles, the distribution trend of the Pf parameter defined by ourselves are different in each particle size range, and the difference between the two particles in the smaller particle size range (about less than 1 µm) seems to be greater than that in the larger one. The relationship between the difference in light-scattering intensity and the elements of the Muller matrix was deduced theoretically. On this basis, the difference in light-scattering intensity of particles with different shapes was calculated by T-matrix. The calculation results show that the method can distinguish spherical and elongated particles well in a certain range of particle sizes (it's approximately 0.3-1.0 µm in diameter). The good agreement between the experimental results and the theoretical calculations indicate the feasibility of the polarized light illuminated scattering characteristics of single airborne particle combined with aerodynamic size information as a new method for aerosol particle shape rapid discrimination.