A periodic array of dielectric rods or holes, known as two-dimensional photonic crystal, is shown to have blazing properties similar to those of classical diffraction gratings. Several different optogeometric configurations are shown numerically to exhibit an almost perfect blazing in the -1st reflected order with a plateaulike spectral dependence in nonpolarized light.
View Article and Find Full Text PDFThe classic differential method is applied for modeling the diffraction of light from two-dimensional photonic crystals that consist of dielectric cylindrical objects. Special attention is paid to mutual interpenetration of consecutive layers. Two algorithms for dealing with a stack of repetitive layers are discussed, namely, the eigenvalue technique and the S-matrix algorithm.
View Article and Find Full Text PDFWe make a generalization of the integral method in the electromagnetic theory of gratings to study diffraction by echelles covered with dielectric lossless or absorbing layers. Numerical examples are given that show that, as in the resonance domain, the diffraction efficiency is more complicated than being a simple product of lossless diffraction efficiency curves and plane surface reflectivity.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
July 2001
The role of the excitation of guided waves propagating in a corrugated dielectric waveguide is discussed in view of the resonance anomalies in reflectivity. Narrow-wavelength filtering properties that are due to these sharp anomalies have been a topic of interest for some time, but a proper understanding of device performances requires an analysis of tolerances with respect to the incident-beam collimation and to waveguide losses. Such an analysis is proposed in this paper, and the conclusion is that the incident-beam divergence plays a critical role in reducing the maximum reflectivity for narrow-band filters.
View Article and Find Full Text PDFMol Med (Sofia)
January 1997
This work reviews clonal rearrangements of T-cell receptor genes in peripheral T-cells of patients with lymphoproliferative diseases. The role of T-cell genes for predisposition to autoimmune diseases is analysed. Methodological approaches for analysis of T-cell receptor repertoire and autoimmune diseases are presented.
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