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Stark J.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm | Rothe T.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm | Kiess S.,Universittsstrasse 38 | Simon S.,Universittsstrasse 38 | Kienle A.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm
Physics in Medicine and Biology | Year: 2016

Single cell nuclei were investigated using two-dimensional angularly and spectrally resolved scattering microscopy. We show that even for a qualitative comparison of experimental and theoretical data, the standard Mie model of a homogeneous sphere proves to be insufficient. Hence, an accelerated finite-difference time-domain method using a graphics processor unit and domain decomposition was implemented to analyze the experimental scattering patterns. The measured cell nuclei were modeled as single spheres with randomly distributed spherical inclusions of different size and refractive index representing the nucleoli and clumps of chromatin. Taking into account the nuclear heterogeneity of a large number of inclusions yields a qualitative agreement between experimental and theoretical spectra and illustrates the impact of the nuclear micro- and nanostructure on the scattering patterns. © 2016 Institute of Physics and Engineering in Medicine. Source


Hohmann A.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm | Voit F.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm | Schafer J.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm | Kienle A.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm
Journal of Physics: Conference Series | Year: 2012

The goal of this study was to investigate the differences between radiative transfer theory and Maxwell theory for simulation of light propagation in a turbid medium. Polarization effects as well as absorbing scatterers with complex index of refraction are taken into account. The simulation volume contained different numbers of scattering and absorbing spheres (radius: 1 μm) and was irradiated from one side with a plane electromagnetic wave (λ 600 nm). The absorption was varied as well as the concentration of the scatterers. The resulting 16 Müller matrix elements were compared for the Monte Carlo method as well as for the Maxwell method for all scattering angles. An increasing absorption of the spheres resulted in larger differences especially for the intensity results (M 11 Müller matrix element) between the two solution methods, while increasing scatterer concentrations led generally to larger differences for all Müller matrix elements. That means that the results of radiative transfer theory have to be treated with care for high scatterer concentrations and large absorption. By using the presented method, differences between the two theories can be investigated for arbitrary particle size parameters (spheres) and optical properties of the scatterers. Source


Hohmann A.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm | Voit F.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm | Schafer J.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm | Kienle A.,Institute For Lasertechnologien In Der Medizin Und Messtechnik Ilm
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2011

A Monte Carlo program for simulation of polarized light propagation in scattering media was developed. By comparing the results of this program (angularly resolved independent Müller matrix elements S11, S21, S34 and S44) with analytical solutions of Maxwell equations, a testing method for Monte Carlo programs simulating polarized light propagation was found. A further goal was to quantitatively point out the differences between solutions of radiative transfer theory and Maxwell theory for polarized light. © 2011 SPIE-OSA. Source

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