Transverse effects under four-wave coupling in the nonlinear Fabry-Perot interferometer

Optics and Spectroscopy - Specific features of the light-beam transverse structure transformation in the process of four-wave coupling in the Fabry-Perot interferometer with a resonant nonlinearity...     

Transformation of optical vortices by polarization dynamic holograms

Results of theoretical and experimental studies of regularities in the transformation of the topological and polarization structures of optical vortices by polarization dynamic holograms formed by pulse Gaussian and singular light beams in dye solutions are presented.     

Order-disorder transformation theory in ternary alloys with face-centred cubic lattice-I.: Equilibrium equations

The atomic ordering of the L 1₂ binary superstructure type in a ternary alloy is investigated. The equilibrium equations of the alloy are given according to the Kikuchi approximation with the account of the atomic interaction energy and the correlation in the first coordination sphere.     

Q-switched Yb 3+ :YVO 4 laser with Raman self-conversion

We report the efficient continuous-wave (CW) and Q-switched laser operation of a diode-pumped Yb:YVO₄ laser. A CW output power of 1 W with a slope efficiency of 59% with respect to absorbed pump power was demonstrated. Passively Q-switched with a Cr⁴⁺:YAG saturable absorber, a Yb:YVO₄ laser with Raman conversion was demonstrated. Q-switched 18.7- J pulses with a pulse duration of 17 ns and a peak power up to 1 kW were obtained at 1018-nm fundamental wavelength and 3.6- J pulses with a pulse duration of 6 ns and a peak power of about 0.6 kW were obtained at 1119.5-nm first-Stokes wavelength.This revised version was published online in March 2005. In the previous version, the published online date was missing     

Spectroscopy and continuous-wave diode-pumped laser action of Yb3+:YVO4

The growth, spectroscopic properties, and laser performance of Yb:YVO4 crystal with laser diode pumping are reported. A peak absorption cross section of 7.4 x 10(-20) cm2 at 985 nm, a radiative lifetime of 0.25 ms, and a stimulated-emission cross section of 1.25 x 10(-20) cm2 at 1008 nm for pi polarization were determined for the Yb3+ ions in YVO4. Continuous-wave laser action of Yb:YVO4 at 1020-1027 nm was demonstrated with an output power of 610 mW and a slope efficiency of 49%.     

Contribution of resonance medium amplitude and phase modulation to the effectiveness of phase conjugation by degenerate four-wave mixing

The contribution of amplitude and phase modulation to the energetic efficiency of wavefront conjugation (WFC) under degenerate four-wave mixing is studied in resonant media simulated by a two- or a three-level scheme. It is shown that a WFC-mirror of reflectivityR higher than unity may be achieved only in the presence of the medium phase modulation. Optimum conditions for obtaining high-efficiency (R>1) WFC are defined.     

The structural characteristics of Zn-Mn ferrite synthesized by spray pyrolysis

The applicability of IR spectroscopy in studies of the structural characteristics of the ferrite spinel phase was shown for Zn_0.5Mn_0.5Fe₂O₄ samples prepared by the pyrolysis of aerosols of aqueous solutions of metal nitrates. The IR spectra of synthesized (ZnMn)Fe₂O₄ ferrites, Fe₂O₃, ZnO, MnO, and Mn₂O₃ pure oxides, and mixtures of these oxides in the region of characteristic M-O stretching vibration and M-O-H bending vibration frequencies were compared to determine the degree of concentration and structural uniformity of the ferrite spinel phase.     

Theory of order-disorder and order-order transformations in binary alloys with b.c.c. lattice—I: Free energy and phase equilibrium equations

The atomic ordering in the four phases: in the phase with short-range order and in the phases with the CuZn (B2), NaTI (B32) and Fe₃Al (DO₃) superstructure types is considered. For an unambiguous representation of the phase free energy on the base of a tetrahedron cluster a generalization of the Kikuchi method made by Hijmans and De Boer was used. The equations for one- and two-phase equilibrium were given.     

Transformation of singular light beam transverse structure in resonant media

The peculiarities of transformation of transverse structure for singular light beams propagating in a resonant medium have been analyzed theoretically. The influence of nonlinear absorption, self-focusing, and defocusing on the characteristics of optical vortices with different topological structure has been studied. The formation conditions and parameters for singular spatially localized structures have been characterized. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 4, pp. 509–515, July–August, 2008.