Spectral determination of μa, μs and g from single and multiple scattering signals with one optically thick sample

Development of robust and easy-to-implement methods for quantitative turbidity characterization by inherent properties of absorption and scattering can have wide applications. We report a new method for multiparameter characterization of turbid samples with three photodiodes based on the radiative transfer (RT) theory. Instead of acquiring collimated transmittance by spatial filtering and scattered light signals by integrating spheres, the method determines RT parameters from forward transmittance dominated by light of single scattering and non-hemispherical diffuse reflectance and transmittance dominated by light of multiple scattering. A Monte Carlo based inverse algorithm has been developed to rapidly obtain absorption coefficient mu(a), scattering coefficient mu(s) and anisotropy factor g at multiple wavelengths. The method has been validated with different sphere suspensions against the Mie theory. RT parameters for suspensions of spheres of 0.966 mu m and 11 mu m in nominal diameter values has been determined in a spectral region of 460-1000 nm and the uniqueness of the inverse solutions has been proved at selected wavelengths. (C) 2020 Elsevier Ltd. All rights reserved.