Modeling of a focused beam in a semi-infinite highly scattering medium

Andreas Tycho

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In recent years, models based on the ”Extended Huygens-Fresnel” principlehas been applied in the description of light propagation in tissue. Thisprinciple was originally developed for light propagation through aerosolsand clear air turbulence. An adaptation of this principle to tissue for theanalysis of Optical Coherence Tomography (OCT) systems is advantageous,because of the convenient description of complex optical systems throughimplication of the ABCD-matrix formalism, and because -contrary to transporttheory and diffusion theory- the phase of the light can be modeled. OCT isoften combined with confocal microscopy by focusing the probing beam. It istherefore interesting to gauge the performance of the Extended-HuygensFresnel theory for a geometry with a focused gaussian beam against a (fortissue) more well established model such as diffusion theory. A new modelof a focused beam in a semi-infinite slab of scatterers using the diffusiontheory is presented here. The model is developed using a Green's functionand a Hankel transform. The performance of both models is gauged againstMonte Carlo simulations for a medium with low loss and highly forwardscattering particles, which is typical of tissue. The model based ondiffusion theory utilizes an exponential phase function, and the implicationof using this phase function instead of the traditionally usedHenyey-Greenstein phase function is investigated. Finally, reasonablequalitative agreement between the three models is shown and discussed.
Original languageEnglish
Title of host publicationSPIE Conference Proceedings, Vol 3597
Publication date1999
Publication statusPublished - 1999
EventConference on Optical Tomography and Spectroscopy of Tissue - San Jose, USA
Duration: 1 Jan 1999 → …


ConferenceConference on Optical Tomography and Spectroscopy of Tissue
CitySan Jose, USA
Period01/01/1999 → …

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