STUDY OF GEOMETRIC SCHEMES OF MULTILAYER OPTICAL MEDIUM

Abstract

Systems of objects, which use optical radiation and study the features of its interaction with these objects, are associated with many areas of scientific and practical research in medicine, pharmacy, biophotometry, chemistry, lighting, etc. These are methods of diagnosis, and methods of analysis of the composition of substances, and methods of measuring the intensity of light. Common to this type of problem, in which it is necessary to determine the intensity of either light or ultraviolet (UV) or infrared (IR) radiation passing through the layer of matter, is the presence of absorption, reflection, concentration, wavelength, layer thickness substances (depths of penetration), etc. in the calculations. Based on the analysis of studies that measure the change in the intensity of optical radiation directed at the object (medium), the expediency of taking into account the geometric elements and boundaries of the optical medium in the modeling of experimental schemes. A separate task is the processing of experimental data (measurement results). These results can be considered accurate if the measurements "at the input" are reduced to certain known or "ideal" conditions and compared with the corresponding "classical" calculation. In many cases, the Bouguer-Lambert-Behr law is used for this purpose. The problems of modeling the interaction of radiation with the object under study can be divided according to the degree of complexity of geometric schemes and components as follows: for elementary geometric objects; for the boundaries (surfaces) of the layer; for both boundaries of one layer of a certain substance through which radiation passes; for the boundaries of the layer and impurities in the substance; for a multilayer medium (more than two boundaries); for the medium with shading of objects (when in the path of radiation there are objects-obstacles that shade, i.e. "overlap" fragments of the boundaries of the layers or particles of the test substance in the layer, or create the effect of "turbidity" of the medium). Methods using normal equations have proved themselves well in many modeling problems for the analytical description of irregular surfaces of objects. This includes the modeling of heterogeneous systems (which are inhomogeneous multilayer optical media) and systems of objects that interact with optical radiation. In view of the above, it is expedient to reduce such problems to purely geometric problems of describing the surfaces of the boundaries of layers and objects inside. The geometric essence of the classification of problems, which corresponds to the classification (types) of problems in studies of the passing of optical radiation through layers of matter, builds a hierarchical structure of modeling the boundaries and elements of optical media.

Key words: geometric modeling, optical medium, optical radiation, boundary surfaces, normal equations.