Bioaerosols Polarization Measurement and Identification by Multi-wavelength Near-Distance Lidar

Abstract

A near-distance polarizatio100n lidar system for real-time standoff detection of bioaerosols was designed developed and developed based on the polarization characteristics of non-spherical particle. Two laser light sources and depolarization components were engaged. The linear polarization purity of laser beam is 97%. The polarization and elastic scattering signal are collected with a Cassegrain telescope of 200mm aperture. In a semi-enclosed bioaerosol chamber, 10 kinds of biological aerosols were mixed and interrogated for linear polarization analysis following the sequence of 355nm, 532nm and 1064nm. It can be concluded that: 1) the depolarization ratios are wavelength-dependent; 2) the identification of bioaerosols can be achieved by through the application of Euclidian correlation degree and Mhalanobis distance.