Recording dynamic holograms in a semiconductor crystal CdF<Subscript>2</Subscript>:In

The kinetics of decay of a phase hologram in a semiconductor CdF₂ crystal with bistable In centers is studied. Kinetic constants of the hologram decay are found, and the potential relief of the bistable center is plotted. The resolving power of the crystal is evaluated and recording of a transparency is demonstrated.     

Electronic excitation energy transfer between dye molecules in H<Subscript>2</Subscript>O and D<Subscript>2</Subscript>O solutions in the micellar phase

Processes of electronic excitation energy transfer (EEET) in H₂O+D₂O solutions within reversed micelles with different degrees of hydration were studied. It is ascertained that the structure of solutions forms a cluster distribution of interacting molecules having a fractal dimensionality. As a result, in regions with a locally high concentration of the dye molecules, an increase in the EEET efficiency is observed. Solubilization by reversed micelles leads to destruction of the cluster structure of the water system, with the dependence of the EEET efficiency on the degree of hydration being nonmonotonic. As the degree of hydration increases, the inhomogeneities of the structure inherent in bulk water are restored.     

Absorption of electromagnetic radiation by an inhomogeneous spherical particle

The cross section of absorption of electromagnetic radiation by an inhomogeneous spherical particle is calculated. The general case of an arbitrary value of the ratio of the particle radius to the radius of the dielectric core is considered. The condition of diffuse reflection of electrons from the inner and outer surfaces of the metal layer of the particle is taken as the boundary condition of the problem. The limiting cases are considered and the results obtained are discussed.     

Computer processing of electronic absorption spectra of rare-earth elements in inorganic laser media

Algorithms and program modules are developed for calculation of the Judd-Ofelt parameters on modern computers. These programs can be used to perform numerical analysis of the energy absorption by rareearth ions in laser media.     

The Two-Body Interaction with a Circle in Time

We complete our previous^{(1, 2)} demonstration that there is a family of new solutions to the photon and Dirac equations using spatial and temporal circles and four-vector behaviour of the Dirac bispinor. We analyse one solution for a bound state, which is equivalent to the attractive two-body interaction between a charged point particle and a second, which remains at rest. We show this yields energy and angular momentum eigenvalues that are identical to those found by the usual method of solving of the Dirac equation,⁽⁴⁾ including fine structure. We complete our previous derivation⁽²⁾ of QED from a set of rules for the two-body interaction and generalise these. We show that QED may be decomposed into a two-body interaction at every point in spacetime.     

Optical amplification of photoinduced polarizability gratings in phosphate glasses

It is experimentally demonstrated that second-order polarizability gratings preliminarily recorded using bichromatic light in a phosphate glass can be amplified under the action of monochromatic radiation. The amplification effect takes place irrespective of the polarization and direction of propagation of the amplifying radiation and is achieved at various wavelengths. The phenomenon is related to the asymmetry of optical transitions between local centers in an isotropic medium in the presence of electric field. It is theoretically shown that this system may feature the formation of alternating electric field domains with dimensions depending on the grating amplitude.     

High accuracy description of radiative return production of low-mass muon and pion pairs at <Emphasis Type="Italic">e</Emphasis><Superscript>+</Superscript><Emphasis Type="Italic">e</Emphasis><Superscript>−</Superscript> colliders

The process of muon (pion) pair production with small invariant mass in electron-positron high-energy annihilation, accompanied by emission of a hard photon at large angles, is considered. We find that the Drell-Yan picture for the differential cross section is valid in the charge-even experimental setup. Radiative corrections both for the electron block and for the final-state block are taken into account.     

Optical third-harmonic generation in coupled microcavities based on porous silicon

The resonance features of the third-harmonic generation have been observed in 1D coupled microcavities consisting of three Bragg reflectors and two identical half-wave layers of mesoporous silicon. The third-harmonic intensity increases by a factor of about 10³ in the resonance of fundamental radiation with each of the modes of coupled microcavities. It has been shown that the resonance positions in the angular spectra of the third-harmonic intensity depend on the coupling between microcavities that is determined by the transmission of the intermediate Bragg reflector. In the framework of the transfer-matrix method with nonlinear sources, it has been shown that the basic mechanism of the enhancement of the third-harmonic generation in coupled microcavities based on porous silicon is the constructive interference of the partial third-harmonic waves that are generated by near-surface layers.