The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
10th International Conference on Laser and Fiber-Optical Networks Modeling (LFNM 2010). 2nd IEEE International Workshop on THz Radiation: Basic Research and Applications (TERA 2010)
Numerical calculations of energy characteristics of quantum-well structures based on Si1-xGex-Si have been performed using the four-band k·p method. It is shown that varying the thickness of the active layer and the height and width of potential barriers one can control the frequency ω of optical transitions. The analytical expressions for ħω are established, which are in good agreement with the numerical...
As-grown ZnO:In crystalline plates demonstrate strong near-band-edge emission related to exciton recombination (380 nm - free excitons; 395 and 406 nm - excitons localized in the impurity centers). Fabry-Perot mode structure is observed for last two bands. Dramatically increasing narrow line (396 nm, Δλ ~ 3.3 nm) is connected with EHP recombination.
Stimulated emission from quantum dots arrays has been observed under optical pumping. The emission has been observed from the ground state for electrons (λ ≈ 1.31 μm) and from two higher levels (λ ≈ 1.21 μm, 1.12 μm). The measured values of the amplification coefficient are rather high, up to 15 ÷ 17 cm-1. Procedure of the amplification coefficient measurements in the active media has been discussed.
A facilities of composite thick films (from 20 to 100 μkm) based on silver nanoparticles in polymethylmethacrylate matrix (Ag-PMMA) as an optical blooming coatings for any optical devices, in particular, silicon cells are investigated. Decreasing of reflection factor for an optical waves more then on 30% from 400 nm to 1100 nm is shown.
CESNET is an association of universities and Academy of science of Czech republic. It is operating a national research and education network (NREN) interconnecting all university cities in the republic. On some lines it it very reasonable to use only one single fiber line. In this paper we discuss technology used on such lines in the CESNET backbone. The key motivation for CLA-based static DWDM systems...
The scattering of Gaussian beam on the metamaterial slab with negative refractive index is considered. Modeling is based on the spectral decomposition of the beam field in plane waves. The effect of different parameters on the polarization characteristics of the electromagnetic field reflected from the metamaterial layer and transmitted through it is investigated. The possibility of control of the...
We investigated numerically the reflectivity of aperiodic multilayer mirrors for broadband supercontinuum reflection. It was shown that multilayer mirror based on TiO2/SiO2 with layer thicknesses changed in the nonlinear way can provide high reflectivity from 468 nm to 1600 nm.
Nonlinear-optical response of metal-alkanoates anisotropic glasses based on cobalt-alkanoate was studied using method of the dynamic holography. Fundamental optical (refractive index n and absorption coefficient α) and nonlinear-optical (nonlinear susceptibilities χ(3) and polarizabilities γNL) parameters of the mesomorphic glasses based on cobalt-alkanoates can be tuned via varying chain length anion...
Double-charge femtosecond vortices were synthesized with the polarization-singularity beam converter [1]. The vortex was focused using moderate and high numerical aperture optics (NA = 0.45 and 0.9) to ablate fused silica and soda-lime glasses. The results demonstrate that the ablation can be controlled on a sub-micrometer scale with a high degree of repeatability.
The experimental results causing the trench of subwavelength nanostructures formation in semiconductor's 4H-SiC surface and inside volume along the femtosecond beam path are considered. The given qualitative explanation of the observed phenomenon is based on universal polariton model of laser-induced material damage with extension of excitation the cylindrical surface plasmon polaritons and their...
Dispersion of linear and non-linear properties of chalcogenide glasses is studied in semi-empirical approach. The process of ultra-short pulse energy deposition into a glass sample is analysed in a numerical model by variation of the Kerr coefficient, multi-photon absorption coefficient and group velocity dispersion coefficient.
In this paper we propose an efficient numerical technique to model the propagation of an ultrashort pulsed optical beam in dispersive dielectric medium. The method has been efficiently used for the modeling of non-dispersive medium. A moving numerical time window along the propagation of the field allows large saving of computational time and memory in comparison with the conventional FDTD to solve...
Structural parameters and physical properties are considered for >100 presently known simple and binary acentric telluride crystals. Distribution of the crystals over point symmetry groups has been defined in comparison with that of selenides. A rosette of ellipses of acentricity has been outlined on the plane of the shortest chemical bond lengths metal-tellurium in the crystal lattice. A set of...
We calculated isotropic and anisotropic Bragg interaction geometry in silicon based 2D photonic crystals with square and triangle lattice. Bragg angle vs. acoustic wave frequency dependencies are presented and compared for both structures. Further research aims and expected effects are defined.
An automatic control technique of the cross-section microstructured optical fibers geometrical parameters is developed. This method can be used both in the control preform and in the process of drawing into an automated process control system for identify and predict the occurrence of the defect.
Influence of spin-polarization effects on the intensity of synchrotron emission from magnetized electron-positron plasma is discussed. In the plasma generated by pair production spin states have polarization-dependent spin bias, whereas in the case of thermodynamical preparation of spin states they are equally populated. It is shown, that radiation intensities from polarized and unpolarized particles...
An optical amplifier followed by a bistable element has been statistically analyzed before. In this manuscript, output noise analysis represents, then signal to noise ratios (SNR) are calculated either for input or output. It will be shown that noise reduction, can be achieved by a proper selection of parameters.
The electromagnetic field amplification constant in the scattering of the nonrelativistic electrons by ions in the elliptically polarized light wave is theoretically studied for any intensities for which radiation amplification takes place. The anomalous amplification effect in the moderate-strong electro-magnetic field is predicted.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.