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Lead-fluoride nano-glassceramics doped with ytterbium and erbium have been developed and synthesized. The influence of heating on the green up-conversion luminescence of erbium has been experimentally investigated. Nano-glassceramics are promising candidates for temperature sensors.
Using the sol-gel technique, BaTiO3 was embedded in opal matrices that are the lattice packings of silica dioxide nanospheres for the first time. The room-temperature IR and Raman spectra clearly show characteristic vibrational modes of the ferroelectrically distorted TiO6 octahedra without any long-range order. Raman spectra bring evidence of a diffuse ferroelectric phase transition in the opal-BaTiO...
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.
We propose ultra-compact all-optical XOR and AND logic gates based on multi-mode interference (MMI) without using nonlinear optics. Numerical simulations show that the least ON to OFF logic-level contrast ratio is 13.3 dB for XOR logic gate and 4.3 dB for AND logic gate in the whole C-band.
We analyze applicability of the ε" <; 0 approximation to wave propagation in active material, comparing the results to the FDTD-based calculation employing more general Maxwell-Bloch model. It is shown that the slab thickness should be less than some critical value, corresponding to the divergence of the Airy series and to the start of the laser generation.
Damping of the polar vibrations determines the real limits of negative dielectric permittivity (DP) region as shown in this work. We obtain the simple quantitative criterion for the negative DP existence in the single oscillatory approximation model. We introduce this criterion as inequality between the damping constant and T-L frequency splitting of the polar phonon. This inequality is the sufficient...
The one-dimensional dielectric photonic crystals with complex defect layers, consisting of ultrathin superconducting and dielectric sublayers are theoretically studied. The pronounced difference in the transmittivity spectra of the photonic crystals with right-handed and left-handed positions of the superconducting defect sublayer with respect to the dielectric defect sublayer is demonstrated. The...
The surface plasmon-polaritons and waveguide modes in prismatic structures are researched. The metallic layer is deposited on glass prism in the first structure and dielectric layer was deposited on metallic film in the second structure. The reflectance from the metallic layer equal zero at assiduously defined parameters. The first structure has high sensitivity of the minimum reflection angle; the...
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...
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.
The fabrication of two types of one-dimensional magnetophotonic crystals based on double-layer Bi-substituted iron garnet films with low and high Bi content as magnetic active layers is presented. Considerable Faraday effect enhancement in the fabricated multilayer structures is reported.
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 have discovered that if input grating coupler is used to excite SEW the generated wave is differed essentially from SEW. This wave is conventionally named “pressed wave” by us. We examine the evolution of wave field with distance from input grating coupler and compare that with analogous dependence for SEW. It is shown that unlike SEW the intensity of pressed wave decreases not exponentially while...
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...
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.
In this paper, the performance of Optical Code Division Multiple Access (OCDMA) system is analyzed at different receivers by using Optical Orthogonal Codes (OOCs). Performance analysis is considered for the chip-level detector and optimum receiver. Our results demonstrate that optimum receiver require less BER i.e. 5.70e-008 than chip-level detector i.e. 2.54e-007 for fixed number of users i.e. for...
We analyze the VIPA demultiplexer for different reflection profiles, i.e., uniform, graded, and Gaussian. It is shown that VIPA demultiplexer characteristics can be improved dramatically by innovative reflection profile engineering. These improvements enhance the performance of demultiplexers in UWB-Over-Fiber systems.
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.
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.
A fiber with a sinusoidal modulation of core diameter was fabricated. Management of the soliton fission by means of this fiber is demonstrated experimentally. Effect of stimulated Raman scattering on the soliton fission is discussed. The experimental observations are confirmed through numerical simulations.
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