Neutrino-Oscillation Searches in the Short-Baseline Gallium Experiment BEST-2 with a 65Zn Source

The possibility of employing a ⁶⁵Zn source in the gallium experiment BEST-2 with the aim of constraining the region of allowed oscillation parameters is examined. The source activity required for the BEST-2 experiment is calculated, and the size of the source and its effect on the results of oscillation measurements are discussed along with the possibilities for producing such a source. Various schemes for implementing respective measurements are considered.

     

A study of the effect of lithium oxide on the spectral properties of potassium-aluminoborate glass activated by chromium ions

The results of designing and studying of potassium-aluminoborate glass activated by chromium and lithium ions are discussed. Changes in the absorption and luminescence spectra of glass after the isothermal treatment are demonstrated. X-ray diffraction data showed the presence of Li(Al₇B₄O₁₇) and Cr₂O₃ nanocrystals with an average size of 20 and 15 nm, respectively. Analysis of the luminescence spectra showed that the Cr³⁺ ions are in a crystalline environment. The luminescence quantum yield was 20–50%, which indicates the prospects for using such materials as a basis for fiber amplifiers in information transmission systems and laser biomedical technologies.     

Two-channel 100-MW microwave compressor for the three-centimeter wavelength range

We present the results of the studies of a 100-megawatt active two-channel compressor of microwave pulses for the three-centimeter wavelength range. The compressors of the transit and reflector types are excited at the TE₀₁ mode of a circular waveguide, and the energy is output by using resonance plasma switches. The channels of the compressors are connected to a microwave oscillator and a load via a special quasioptical 3-dB directional coupler with enhanced electric strength. The use of the quasioptical coupler allows one to ensure the decoupling of the input microwave line (by about 20 dB) and combine coherently the pulses compressed in each of the compressor channel. High-and low-power tests of the compressors have been performed and the wave phase in the compressed pulses has been measured. The pulses obtained for an incident power of 5 MW have a power of 40–53 MW, a duration of 40–60 ns, and a power gain greater than 10. The compression efficiency amounts to 55%. The stability and good reproducibility of the amplitude and frequency characteristics of the radiation from a two-channel compressor make it promising for use in the linear accelerators of charged particles. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 8, pp. 660–674, August 2008.     

Some properties and applications of biphoton states of three-mode light

Statistical properties, generation, and applications of three-mode biphoton fields with no more than one photon in each mode are discussed. Such field states have sub-Poissonian photon statistics and can be squeezed and entangled. The modes that simultaneously exhibit these properties in measurements are indicated. Two setups for generating such states via spontaneous parametric down-conversion are described. It is shown that the field states discussed in this study provide a quantum channel for teleportation, dense coding, and quantum key distribution.     

The influence of the interface between two media on the structure of the electromagnetic field scattered by a nonlinear half-wave loop

In an approximation of weak nonlinearity, we study experimentally and theoretically the scattering of a plane electromagnetic wave by a ring loop containing a nonlinear local load in the presence of a plane interface between two media. A number of patterns are detected in the structure of the field scattered at higher harmonics, which can be used in the development of nonlinear markers intended for rescue systems.Radiophysical Research Institute, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 9, pp. 961–968, September, 1995.     

On preparation of the entangled W-states from atomic ensembles

We describe how three atomic ensembles can be prepared in entangled states of the W-class via the Raman type interaction of a strong classical field and a projection measurement. The constructed atomic entanglement consists of the Dicke or the W-states of each of the ensembles.     

Thermodiffusional stratification of a continuous microwave discharge plasma

We report the results of investigations of a continuous microwave discharge ignited in a quasioptical resonant cavity. We study a new phenomenon for such a discharge: a small-scale stratification of the plasma in the direction perpendicular to the electric field vector. This stratification is observed in a plasma with electron density higher than the critical density at the microwave frequency and is due to the development of a thermocurrent instability. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 8, 537–542 (25 April 1998)     

Features of propagation of laser radiation in media with small-scale periodic inhomogeneities

The problem of laser-radiation propagation in media with small-scale periodic phase inhomogeneities is considered analytically. Relying on our analytical treatment and numerical calculations performed in the diffraction approximation, we demonstrate the effect of periodic self-reproduction of the field structure of radiation during its propagation in media with small-scale periodic inhomogeneities, which is similar to the Talbot effect in a homogeneous medium.