Spectroscopy of the Surface Polaritons in the CdXZn(1-X)P2 Solid Solutions.

Here we report on the analysis of the effect of the doping of CdP2 single crystals by ZnP2 nanoclusters on the dispersion of the surface polaritons (SP). The ATR spectroscopic technique has been applied to excite the SP in the CdXZn(1-X)P2 system. Analysis of the obtained spectra has shown that the doping of CdP2 single crystals by ZnP2 nanoclusters result in the position and the width of the dispersion branches of the SP. This effect is more pronounced in the low frequency dispersion branches. These SP branches are originated from phonons which correspond to the motion of the cation sublattice.

Dispersion of Phonon Surface Polaritons in ZnGeP2: Anisotropy and Temperature Impacts.

Zinc germanium diphosphide (ZnGeP2) is an attractive and promising functional material for different devices of the nano- and optoelectronics. In this paper, dispersion of phonon surface polaritons (PSPs) in ZnGeP2 has been studied in the 200-500-cm(-1) spectral range at 4 and 300 K. Dispersion of "real" and "virtual" PSPs were calculated for C-axis being normal and parallel to the surface. Anisotropy in ZnGeP2 leads to the different numbers of PSP dispersion branches for different orientations of the sample. The temperature-dependent phonon contributions in the dielectric permittivity shift dispersion of the surface polaritons in ZnGeP2 to the higher wavenumbers at 4 K. We have shown that experimental dispersion of PSP is in agreement with theory.

Homogenization of quasi-1d metamaterials and the problem of extended bandwidth.

We derive approximate analytical expressions for the effective permittivity tensor of two-phase metamaterials whose geometry is close to one-dimensional (quasi-one-dimensional metamaterials). Specifically, we consider the metamaterial made of parallel slabs with width given by a linear or parabolic function. Using our approach, the design of epsilon-near-zero, ultra-low and high refractive index metallodielectric metamaterials with extended bandwidth has been demonstrated. In addition, generalizations to the three-dimensional case and some limitations of the presented technique are briefly considered.

Molecular ruler based on concurrent measurements of enhanced Raman scattering and fluorescence.

We report a way to assess the separation between a molecule and a metal surface on account of both Raman scattering and fluorescence intensities measured simultaneously. This approach has no need for an accurate quantity of molecules and bears 1 nm resolution. Its distance sensitivity is experimentally demonstrated in the case of dye molecules lying on a gold surface with a polymer spacer layer in between and is compared with theoretical prediction.

[Remote infrared thermography: achievements, current potentials, and perspectives].

The article presents obtained results on using remote infrared thermograph in medical practice in Ukraine. It was shown that appearance of domestic thermographs with matrix photoreceiver enhances considerably an area of their use. New results related to diagnosis of a patient's state were obtained. Taking into account that this method is harmless, not difficult to perform, allows carrying out diagnostics many times during treatment and appearance of a new type of thermographs with high temperature sensitivity, it is necessary to renew the use of remote infrared thermography in medical practice in Ukraine.

Percolation threshold for Bruggeman composites.

Using a simple phenomenological approach, we calculate the percolation threshold for Bruggeman composites having microgeometry of two kinds. Both kinds of composites consist of spheroids whose shape follows the Beta distribution. At the same time, the first one is a mixture of spheroids equally oriented along their revolution axis. In this case the percolation threshold is shown to be the same as for an assembly of equally oriented identical spheroids whose shape corresponds to the most probable shape of the distribution. For such composites the percolation threshold can vary between 0 and 1. The second one is a random mixture of the spheroids. In this case the percolation threshold is expressed in terms of the Gauss hypergeometric function; it is shown to vary between 0 and 1/3. The derived analytical results are supplemented with numerical calculations carried out for different values of the Beta distribution parameters.

Analysis of the response of planar polarization interferometer to molecular layer formation: fibrinogen adsorption on silicon nitride surface.

The most sensitive optical method of interferometry was exploited for determination of changes in the refractive index following the adsorption of biological molecules onto the solid surface. Instead of having two waveguiding arms (the main and the reference) in traditional Mach-Zhender interferometer, two ortogonal TM and TE modes propagating through the SiO(2)-Si(3)N(4)-SiO(2) waveguide structure were employed in planar polarization interferometer (PPI). Multiperiodic PPI response was, therefore, formed due to the phase shift between TM and TE modes. A matrix simulation procedure was developed in order to investigate the influence of both the refractive index and molecular layer thickness on the PPI response. Nonspecifical binding of fibrinogen to silicon nitride surface was studied as a model object for PPI testing. The results obtained are in good agreement with the known information about fibrinogen adsorption on the different surfaces. An attempt to introduce the concept of 'surface molecular concentration and molecular polariziability' instead of 'molecular layer thickness and refractivity' was undertaken.

Elastic laser light scattering by GaAs surfaces.

Angle-resolved scattering (ARS) intensities were measured in the backscattering hemisphere for the (1 0 0) and (1 1 1) faces of GaAs single crystals. Three epitaxial layers were deposited onto the GaAs (1 0 0) single-crystalline wafers. The laser elastic light scattering shows the presence of a regular surface microrelief whose orientation corresponds to the crystallographic axes in the surface plane. We studied the statistical properties of this microrelief and determined the parameters that characterize the surface. We propose to use the ARS ratio for two wavelengths (in our case, 632.8 and 441.6 nm) to determine the topographical properties of scattering and to study crystal surface defects.