The Study On The Association Between Multidimensional Elastic Light Scattering And The Morphology Of Superficial Biological Tissue

Elastic light Scattering, ELS, is the technology based on the Maxwell's Equations or Radiative Transfer Equations, to solve light propagation in inhomogeneous medium like biological tissues, and the inverse theory. The analytic solutions, or named multidimensional elastic scattering field, contains a huge amount of information, such as angular distribution, spectrum distribution, polarization information, etc. This kind of integrated field is more informative than traditional one point intensity field, so a super resolution far below traditional light diffraction limit can be expected. In matter of fact, researchers have done a lot of study on it, especially, for biological tissue scattering problems, many groups have done some interesting researches and get some useful deductions.For century, light propagation theory in biological tissue is a challenge because of its structures'complication and varieties. Researchers cannot reach a rigid and universal analytic solution for this problem, So they find a substitution that they treat biological tissue as a combination of independent optical micro-element abstractly, which has its own optical properties, and the tissue optical property is a combination of single ones. This research approach is named Radiative Transfer Theory, and this theory is universal for different kinds of tissue, but the light propagation in biological tissue is more complicated than this, and light propagation should tell us something more about a special kind of tissue structure. Obviously, the Radiative Transfer Theory cannot do this and a rigid analytic solution based on the Maxwell's Equations cannot be reach. Fortunately,the interaction between light and tissue can be properly modeled under some circumstances, for instance the superficial tissues, which are located at the superficial of tissue, the scattering problem.We focus our attention on this superficial tissue scattering problem, forward and backward. The inverse problem is based on the forward problem and our ultimate goal, so firstly we do some research on the forward problem. Generally, tissue fall into discrete random medium and continuous random medium, according to its structures. We model them, do some simulation, and finally the experiments, and more time and attentions are paid to the integrated model based on the normal two. We have four parts here.Part 1. Introduction, we talk about our research background, our research contents, and research method. Part 2. Basic theory. We study the theory of light scattering of discrete random medium and continuous random medium, and try to combine the two into one. Part 3. Simulations and experiments. Some simulations.based on FDTD(finite-different time-domain) method can be done before the the experiments for test and verify, then we do the tissue phantom(polystyrene sphere) experiments, plant tissue in vitro experiments, and animal tissue in vitro experiments successively. Part 4. Summary and the future work. We summarize our work and draw a conclusion. What's more,we talk about several proper directions of future work.