Optical tomograph with photon counting and projective reconstruction of the parameters of absorbing 'phantoms' in extended scattering media

Abstract

A semi-classicai theon, of the non-linear miniband condLction n crossed electric and magnetic fields is presented The Bo.tzmann transport equation is solved with realrstic scattering mechanisms. i.e. electron-phonon scartering and interface potent al fluctuat;ons. The technique conssts of a characteristic solation of tne electron dynamics along tne free trajectories associated with an terative convergent algorithm. The main effect of the transverse magnetic field is interpreted n the frame of the Esaki-Tsu model by the modification of the free trajectories by the Lorentz force which repels t h e onset of Bragg scattering to higher electric f elds A direct comparison W th experimentalcurrent-voltage data is performed in taking into account the electric field inhomogeneity. Free trajectories in k-space

Fast visualization of internal structure of multiple-scattering objects by diffusion optical tomography

“…In [30][31][32], for fast reconstruction ofthe diagnosed object internal structure, an approximate statistical nonlinear algorithm of OT inverse problem solution has been suggested. In this algorithm, we suppose that a difference between the output photon flux I'] in a spatially homogeneous case (in the absence of absorbing and/or scattering <<inclusions>>) and the output photon flux (J) in a spatially inhomogeneous case (in the presence of such inclusions) results from the inclusion appearance.…”

“…The approbation has been performed by the example of reconstruction of a rather complicated (in relation to [30][31][32], up to three strongly absorbing inclusions with size 5 mm) Moreover, we (c) have presented here some first results of these algorithms approbation.…”

“…To do this, one must select a small (<useful>>) part of the output photon flux from a full flux of the detected output photons by means of certain criteria. Because the diffusion OT hardware enables one to perform all the needed measurements during only some minutes [30][31][32], one need to develop an approximate algorithm, which makes possible to reconstruct the object internal structure during about the same time. All OT techniques can be classified on the basis of ways of such selection.…”

Investigation of the interaction of femtosecond laser radiation with biotissues by the optoacoustic method

“…For example, if such problem is solved by the projection method [2,3], distributions of the probability of the registered photons transmitted through the examined object must be known. Correct reconstruction of the distribution of light-absorbing inhomogeneities in these media calls for exact measurements of the optical characteristics of scattering media.…”