M. P. Lisitsa

Self-induced resonant optical rotation in crystals KCl:Li

Abstract The specific rotation of the resonant radiation polarization plane predicted earlier for cubic crystals with tunneling centers is observed in KCl containing FA(Li) centers. The rotation is supposed to be connected essentially with the well-known off-center position of Li+ ion. The simple theory based on this assumption agrees with the experimental data.

Optical properties of quasi-zero-dimensional CdSXSe1-X crystallites grown in a glass matrix

The analysis of the linear and nonlinear optical properties resulting from quantum confinement in CdSSe-doped glasses is reviewed. The growth technology and the data obtained by x-ray diffraction and transmission electron microscopy methods are also reviewed. Analysis of the influence of sizes, composition, and the dispersion of these values on both charge carrier energy and optical (absorption and photoluminescence) spectra is carried out. The peculiarities of the absorption saturation processes related to the quantum confinement, the surface recombination, and the hexagonality of microcrystals randomly oriented in the glass matrix are discussed.

Determination of the parameters of semiconductor quantum dots in glassy matrices from the absorption and luminescence spectra and from saturation of the optical absorption

Optical methods are described for determining the parameters of semiconducting quantum dots synthesized in a glassy borosilicate matrix. The limitations of these methods and the magnitudes of their errors are analyzed. The parameters of CdSxSe1−x nanocrystals in the commercial glasses KS-10, OS-12, Corning 2–61, and other experimental samples are determined.

THE RAMAN SPECTRA OF THE FAMILY CRYSTALS CS3BI2BR9, RB3BI2BR9 AND RB3SB2BR9

Abstract In the present work the Raman spectra of the family of ferroelectric crystals A3B2C9 (where A = Cs, Rb; B = Sb, Bi; C = Br) are given and the assignment of some high-frequency bands is fulfilled. Conclusions about possible differences between the structure of Rb3Bi2Br9 and Rb3Sb2Br9 crystals from the well-known and detailed structure of Cs3Bi2Br9 crystals are made. We also suggest that the significant variation between the spectra in the temperature range 77–300 K can be not only due to phase transition effects but also to anharmonic Fermi resonance between one- and two-phonon excitations.

Antiresonance in the phonon spectrum of mixed crystals Zn1−xCdxSe

Abstract The effect of discrete-continuum interference of one-phonon and two-phonon states in mixed crystals Zn1−xCdxSe is experimentally observed by Raman spectroscopy. It causes the considerable line-shape asymmetry of the TO-mode and dip antiresonance which changes significantly with the composition range.

Raman scattering in A3B2C9 ferroelectric crystals

Raman spectra of some A3B2C9 ferroelectric crystals (here A=Cs, Rb; B=Sb, Bi; C=Br) have been obtained, and a number of high-frequency bands have been assigned. The Rb3Bi2Br9 and Rb3Sb2Br9 crystals are shown to differ in structure from Cs2Bi2Br9. The qualitative changes in the spectra in the 77–300 K temperature interval can be associated not only with structural phase transitions, but with the effect of the anharmonic Fermi resonance between one-and two-phonon excitations as well.

Effect of polarization self-action in cubic crystals: peculiarities and applications

New concepts are developed to describe a wide area of nonlinear systems involving the phase relaxation peculiarities for the degenerate two-level system under the resonant optical excitation. Nonlinear susceptibility of the two-level system becomes anisotropic, and self-induced changes of polarization (SICP) are developed to the large (gigantic) magnitudes. The nonlinearities of two different natures are considered: the saturation of absorption and the resonant optical reorientation of anisotropic defects. For these particular cases, the SICP effects manifest themselves at a field much lower than that in traditional nonlinear optics. The larger magnitudes of the effects offer good possibilities for the development of optical devices based on the new physical principles. Various applications of SlOP effects are demonstrated, including the spectroscopic investigations of impure cubic crystals, optical diagnostics, optical storage, information processing, and the development of new optical devices.

CdSSe-doped glasses as the optical device material

Energy levels structure of the CdSxSe1-x microcrystallites in the glass matrix has been obtained from the analysis of the absorption spectra taking into account the crystallite random orientation, the confinement effect and the dispersions of both microcrystallite radius and composition. The peculiarities of the absorption saturation have been determined.

Physical Mechanisms Of Optical Nonlinearity In Impure Cubic Crystals: Polarization Study

Here we report on some results of investigation of the physical mechanisms responsible for optical nonlinearity in cubic crystals with tunneling centers. The nonlinear susceptibility of the system becomes anisotropic under the resonant polarized photoexcitation of the intracenter electronic transition. This anisotropy manifests itself in the self-induced change of light polarization which may form the basis of the nonlinear polarization spectroscopy. We use this experimental technique for the investigation of reorienting FA and F2 centers in KCl.

Resonant secondary emission spectra of optically aligned hot excitons in ZnTe: Effect of the excitation intensity

Abstract The variation of the multiphonon LO-lines polarization degree and the sublinear dependence of their intensity on the pumping level have been established. The results explained in view of both the transverse and the longitudinal relaxation of the real intermediate states.