title: Comparative Raman study of transparent and turbid materials: models and experiments in the remote sensing mode.
abstract: The influence of turbidity on the Raman signal strengths of condensed matter is theoretically analyzed and measured with laboratory - scale equipment for remote sensing. The results show the quantitative dependence of back- and forward-scattered signals on the thickness and elastic-scattering properties of matter. In the extreme situation of thin, highly turbid layers, the measured Raman signal strengths exceed their transparent analogs by more than a factor of ten. The opposite behavior is found for thick layers of low turbidity, where the presence of a small amount of scatterers leads to a decrease of the measured signal. The wide range of turbidities appearing in nature is experimentally realized with stacked polymer layers and solid/liquid dispersions, and theoretically modeled by the equation of radiative transfer using the analytical diffusion approximation or random walk simulations. Graphical abstract Spatial Raman emission profiles in transparent and turbid materials.
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany. dieter.oelkrug@uni-tuebingen.de.
authors.forename: Dieter
authors.initials: D
authors.lastname: Oelkrug
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.|Process Analysis and Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Boldrini
authors.affiliation: Process Analysis and Technology, Reutlingen Research Institute, Reutlingen University, Alteburgstr. 150, 72762, Reutlingen, Germany. karsten.rebner@reutlingen-university.de.
authors.forename: Karsten
authors.initials: K
authors.lastname: Rebner
keywords: Diffuse light scattering; Monte Carlo simulations; Raman spectroscopy