A. F. Konstantinova

Optical and nonlinear laser properties of the χ(3)-active monoclinic α-KY(WO4)2 crystals

Monoclinic α-KRE(WO4)2 crystals are grown. Their structure is described in two crystallographic settings. The principal refractive indices are determined and the coefficients and characteristic wavelengths are used for calculating refractive indices by the Selmeyer formulas. The data on the anisotropic parametric Raman generation in these crystals under the picosecond pumping are discussed.

Refractive indices of laser nanocrystalline ceramics based on Y3Al5O12

Refractive indices of the nanocrystalline Y3Al5O12 ceramic and a garnet single crystal of the same composition have been measured. In the visible and near IR range (0.4–1.064 μm), the prism method was used; in the medium IR range (2–6.2 μm), the interference method with the use of thin plates was applied. The refractive indices of these crystalline materials are practically the same over the entire spectral range studied and are described by the approximate formula proposed earlier for a single crystal. The parameters of the continuos-wave lasing in the nanocrystalline Y3Al5O12 ceramic doped with Nd3+ and Yb3+ ions measured recently are presented.

Modern application packages for rigorous solution of problems of light propagation in anisotropic layered media: II. Optically active crystals

The matrix Δ suggested by Berreman for optically active crystals of various symmetry classes has been calculated with the use of the Mathematica-4.1 package. It is shown that the eigenvalues of this matrix are the refractive indices, whereas its eigenvectors determine the polarization states of eigenwaves propagating in the crystal. The relation between the components of the gyration tensors obtained on the basis of various constitutive equations is established. The essential differences in the optical activity described on the basis of these equations are also discussed.

The absorption and circular dichroism spectra of langasite family crystals doped with chromium ions

The absorption and circular dichroism spectra of langasite family crystals, La3Ga5SiO14, La3Ga5GeO14, Ca3Ga2Ge4O14, Sr3Ga2Ge4O14 (red), Sr3Ga2Ge4O14 (green), La3Ta0.5Ga5.5O14, and La3Nb0.5Ga5.5O14, which were doped with chromium ions, have been investigated in the range of 240–850 nm. It is shown that chromium ions are incorporated into the structure of the investigated crystals both in the octahedrally (Cr3+ ion in 1a octahedron) and tetrahedrally (Cr4+ ion in 2d tetrahedron) coordinated positions. The ion ratio Cr3+/Cr4+ changes in a wide range in the crystals studied.

Experimental and theoretical determination of the optical rotation in langasite family crystals

Optical properties of 21 langasite family crystals of different compositions have been studied. Dispersion dependences of the specific optical rotation for light propagation along the optical axis are experimentally obtained for La3Ta0.25Ga5.25Si0.5O14, La3Ta0.25Zr0.5Ga5.25O14, and La3Zr0.5Ga5Si0.5O14 crystals. Based on the known refractive indices of six crystals, the refractive indices for 15 crystals are calculated by the method of molecular refraction. Based on the experimental data, the dependence of the specific optical rotation for light propagation along the optical axis on the birefringence is plotted for 10 crystals. Using this dependence, the specific optical rotation is estimated for 11 more crystals of different compositions. Based on X-ray diffraction data, the specific optical rotation is calculated by the WinOptAct program for 13 crystals. The application of different methods makes it possible to predict the optical characteristics of langasite family crystals of different compositions.

The influence of optical activity on the intensity and polarization parameters of transmitted light in crystals

The ellipticity and azimuth of light transmitted through an optically active plate and the intensity of this light transmitted through an analyzer are theoretically investigated as functions of the rotation angle of the plate. Relationships describing these parameters are considered. It is demonstrated that, depending on the angle of inclination of the plate, the optical activity can affect the characteristics of the transmitted light differently. A technique for determining the optical activity parameters is proposed from analyzing the relationships for the light intensity. The conoscopic figures of uniaxial and biaxial optically active crystals are described.

Lasing and refractive indices of nanocrystalline ceramics of cubic Yttrium Oxide Y2O3 doped with Nd3+ and Yb3+ ions

A continuous-wave lasing at 1 μm was excited by the radiation of semiconductor laser diodes at room temperature in nanocrystalline ceramics Y2O3 doped with Nd3+ and Yb3+ ions. The refractive indices of the undoped nanocrystalline Y2O3 ceramics were measured in the wavelength range 0.4–9 μm.

Modern application packages for rigorous solution of problems of light propagation in anisotropic layered media. I. General solution of boundary problems in crystal optics

A new approach to the solution of the boundary problems of light propagation in optically active anisotropic absorbing media has been suggested. Unlike a number of already existing approaches, the new approach is based on the use of a computer mathematical system—the integrated application package Mathematica-4.1 and the method suggested by Berreman. It is shown that the special functions integrated into the package allow one to calculate the characteristics of the reflected and transmitted light for an arbitrary class of crystals and construct their dependences on various optical parameters. The examples of the application of the package Mathematica-4.1 for solving various problems of crystal optics are considered.

Calculation of the Refractive Indices of M1-xRxF2+x Crystals (M = Ca, Sr, Ba, Cd, Pb; R are Rare Earth Elements)

It is shown that the refractive indices of two-component M1-xRxF2+x crystals (M = Ca, Sr, Ba, Cd, Pb; R = La-Lu, Y; 0 ≤ x ≤ 0.5) can be calculated with a rather high accuracy in a wide spectral range (depending on the rare-earth-element content) using molecular refraction additivity for the components.

Investigation of the optical properties of KGd(WO4)2:Nd3+ crystals with allowance for absorption

The optical properties of a biaxial absorbing KGd(WO4)2:Nd3+ crystal have been investigated. The main refractive indices were measured in the visible spectral range and the absorption and transmission spectra of samples of these crystals were studied. The changes in the refractive indices were in the region of the absorption bands with the use of the Kramers-Kronig relation. Conoscopic pictures of this crystal in the regions of transparency and absorption bands were calculated and are presented.