Polarization signatures of airborne particulates

Abstract

Abstract. Exploratory research has been conducted with the aim of completely determining the polarization signatures of selected particulates as a function of wavelength. This may lead to a better understanding of the interaction between electromagnetic radiation and such materials, perhaps leading to the point detection of bio-aerosols present in the atmosphere. To this end, a polarimeter capable of measuring the complete Mueller matrix of highly scattering samples in transmission and reflection (with good spectral resolution from 300 to 1100 nm) has been developed. The polarization properties of Bacillus subtilis (surrogate for anthrax spore) are compared to ambient particulate matter species such as pollen, dust, and soot. Differentiating features in the polarization signatures of these samples have been identified, thus demonstrating the potential applicability of this technique for the detection of bio-aerosol in the ambient atmosphere.

Laboratory evaluation of the scattering matrix of ragweed, ash, birch and pine pollen towards pollen classification

“…Likewise, image recognition on the scattering pattern of pollen grains have been investigated, as described by Šaulienė et al (2019), and holographic images are also used (Giri et al, 2019;Sauvageat et al, 2020;Kemppinen et al, 2020) as an identification methodology. Finally, light scattering by pollen has been studied in the laboratory in aqueous solutions by Bickel and Stafford (1980) or when pollen are deposited on a substrate or a holder by Surbek et al (2011), Iwai (2013), Raman et al (2013) and Nouri et al (2018). Concerning airborne pollen, Matsuda and Kawashima (2018) and Holler et al (2016) studied forward and side scattering while polarization-dependent features of light scattering were first studied by our group by evaluating the scattering matrix of ragweed pollen in laboratory ambient air at near-backscattering angles (Cholleton et al, 2020).…”

Laboratory evaluation of the scattering matrix of ragweed, ash, birch and pine pollens towards pollen classification

“…Likewise, image recognition on pollen grains holographic images is also used (Giri et al, 2019;Sauvageat et al, 2020;Kemppinen et al, 2020) as an identification methodology. Finally, light scattering by pollens has been studied in laboratory in aqueous solutions by (Bickel and Stafford, 1980) or when pollens are deposited on a substrate or an holder by (Surbek et al, 2011;Iwai, 2013;Raman et al, 2013;Nouri et al, 2018). Concerning airborne pollens, (Matsuda and Kawashima, 2018;Holler et al, 2016) studied forward and side scattering while polarization-dependent features of light scattering were first studied by our group by evaluating the scattering matrix of ragweed pollen in laboratory ambient air at near backscattering angles (Cholleton et al, 2020).…”

Laboratory evaluation of the (VIS, IR) scattering matrix of complex-shaped ragweed pollen particles

“…The sensitivity of light scattering to the pollens size and shape has been studied for several decades when pollen grains are embedded in aqueous solutions [30] , [31] , [32] . More recently, light scattering by pollens has been studied when pollens are in a fixed orientation as deposited on a holder in [33] , [34] , [35] or more recently in [36] . Concerning airborne pollens, forward and side scattering have been compared in [37] and the spectral dependence of forward light scattering patterns has been studied in [38] , without however considering the light polarization property, which may be vary during the scattering process for non-spherical particles [39] , as for ragweed pollen particles.…”