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On the basis of solution of the problem of the electromagnetic wave diffraction by a transparent fiber with the circular cross-section, we have deduced expressions linking the positions of the first diffractive minima and diameter of the fiber. These equations have been used to determine the diameter of the fiber. Scattered-field pattern have been recorded with a digital camera. The obtained picture...
Transient pulsed excitation of the localized surface plasmons on nanowire and nanoshell is visualized and analyzed. The complex source point concept is used to simulate an incident transient beam. Rigorous mathematical method based on the Laplace transformation is applied. Time domain field representation is obtained through the evaluation of the residues at singular points associated with the eigenvalues...
Proposed, justified and tested measuring of beam spatial coherence based on the detection of an interference visibility of the two reflected beams from the rotated plane-parallel plates. Hie specificity of measuring consists in dependence of the interference contrast from the longitudinal time delay and transverse shift of named replicas simultaneously. Accurate measurement of the angular position...
Application of holography methods open new possibilities of constructing holographic television systems (HTS) that provide salient, multi-angle and interference-resistant images of extended scenes and three-dimensional objects. HTS, which synthesizes three-dimensional holograms and restore the images of three-dimensional objects, can be realized thanks to obtaining the third coordinate (the scene...
Extraordinary dispersion features of both bulk and surface polaritons in a magnetic-semiconductor superlattice which is influenced by an external static magnetic field applied in the Voigt and polar geometries are revealed and discussed. It is shown that the conditions for total overlapping dispersion regions of simultaneous existence of bulk and surface polaritons can be reached providing a conscious...
Electrical dc conductivity and relative dielectric permittivity (1 kHz, 0.05–35 MHz) of SiO2-based porous materials containing squarylium, polymethine, rhodamine 800 dyes and rhodamine 6G in methylmethacrylate are investigated. Peculiarities of the influence of dye and temperature on the dc conductivity and the dielectric permittivity of the materials are determined.
Terahertz laser with a continuously variable feedback is described. The direction and the diameter of the output beam are not changed during adjustment. The laser resonator has a possibility of additional output unregulated radiation beam on the laser control device.
A review of last results obtained in the field of supercontinuum generation in all normal dispersive optical fibers is provided. A close attention is devoted to the results obtained recently in our group. They reveal the crucial role of dispersion profile impact on SC generation in ANDi PCFs. Found optimal fiber profiles show the way for designing of novel ANDi PCFs which would allow potentially extend...
Considered is the two-dimensional (2-D) source-free problem of the H-polarized electromagnetic field in the presence of a silver circular nanotube coated with a concentric layer of active material and with a core of similar active material. We assume that the natural-mode frequency is real-valued and look for it together with the threshold value of material gain in the active regions. As a method,...
Microchip lasers are very efficient, compact and convenient sources of coherent light. However they have a serious disadvantage that, especially in high power operation regimes, the emitted beam structure is relatively bad (with large angular divergence). We show that the intracavity photonic crystals with spatial filtering functionality, can strongly improve the spatial characteristics of the microchip...
This work describes methods for filtering of several simplest types of digital holographic interferogram. The methods are suitable for the case of sine and tangential contrast of interference fringes. Filtering procedure improves quality of the interferogram by eliminating their parasitic speckle modulation that gives an opportunity to improve the quality of interferogram.
We proposed and investigated two-channel photonic crystal demultiplexer that has much smaller dimensions than those used currently in existing optical transmission systems. We also studied the propagation of the TE wave through the investigated photonic crystal demultiplexer.
The features of the Talbot wavefront sensor with the adaptive LCD SLM grating are discussed. The influence of the aperture effect on the sensor accuracy is considered by computer simulation. The experimental investigation of the wavefront reconstruction error depending on the grating fill-factor is carried out.
Lasers can be useful not only in the obvious "hardware" application for the generated "soup" composition controlling by different methods of laser spectroscopy, but also in the generation of perspective hypotheses
We investigated the dynamics of electron excitations in plasmonic nanocomposite based on a polymer matrix with a periodic substructure of ordered silver nanoparticles. The nanoparticles were synthesized in the polymer matrix from a metal precursor periodically distributed by holographic method.
The nonlinear optical response is detected in hybrid liquid crystal (LC) cells, which are fabricated by using nonuniform substrates, namely photonic crystals with periodic microstructures etching on Si plates. The main nonlinear mechanism exploited in the hybrid LC cells was the orientation nonlinearity in bulk pure nematic 5CB due to surface induced photorefractive effect. The effective Kerr nonlinear...
The giant resonant excitation of the second harmonic of THz radiation in planar "dielectric — graphene — dielectric…" metamaterial is investigated. Oblique incidence of sand p-polarized first harmonics is considered, using kinetic and hydrodynamic approaches. The reflection into the second harmonic reaches the values of 0.1 for intensities and more.
One of fundamental problems of electro-magnetics is the scattering of a plane wave from a grating of infinite circular dielectric cylinders (wires). Lord Rayleigh was apparently one of the first researchers who formulated it in the XIX century. We consider the associated lasing eigenvalue problem and focus our attention on the asymptotic approximations of the eigenvalues for large values of the ratio...
The dispersion and polarization properties of the electromagnetic waves in a multilayered structure composed of a magneto-optic waveguide on dielectric substrate covered by a one-dimensional dielectric photonic crystal are investigated theoretically. Different regimes of modes propagation inside such structure depending on the system parameters are studied.
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