Light transport in anisotropically scattering and absorbing media

Ozan Akdemir

Research output: ThesisPhD Thesis - Research UT, graduation UT

77 Downloads (Pure)

Abstract

Understanding the transport of light in photonic scattering media is crucial for many application areas, such as atmospheric and climate sciences, oceanography, biophysics, powder technology, printing, solid-state lighting, and satellite observations. Transport theory describes the propagation of waves in scattering media, notably in a widely-used realistic situation like a slab in three dimensions (3D). The basic differential equation used in transport theory is the radiative transfer equation, which is equivalent to Boltzmann’s equation used in the kinetic theory of gases and neutron transport. A popular method describe light propagation in multiple scattering media is the Monte Carlo simulation of light transport, a statistical method that converges to the exact solution of the radiative transfer equation. To obtain a high accuracy, however, this method comes with the cost of extremely long computation times and high computational power requirements. Alternatives to the Monte Carlo simulations are analytical approximations to the radiative transfer equation, such as the PN approximation. Analytical methods are still significantly faster than the Monte Carlo simulations, and in certain configurations, the results of these analytical approximations match the accuracy of simulations.
In this thesis, we study the light transport through photonic scattering media, specifically the position dependent energy density, by using the transport theory and experimental observations. We specifically focus on samples that consist of anisotropically scattering and absorbing scatterers, as common approximations to the radiative transfer equation fail for these samples and one is thus interested in the possible description in these regimes. We perform experiments to measure the position-dependent energy density inside 3D and quasi-2D samples that are in these regimes. Our results provide a better understanding of such samples, and provide a guideline to the applicability of analytical models as an alternative to Monte Carlo simulations.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • University of Twente
Supervisors/Advisors
  • Vos, Willem L., Supervisor
  • Lagendijk, Ad, Co-Supervisor
Award date14 Sept 2023
Place of PublicationEnschede
Publisher
Print ISBNs978-90-365-5779-5
Electronic ISBNs978-90-365-5780-1
DOIs
Publication statusPublished - Sept 2023

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