Laser Annealing of Thin-Film Ferroelectric Heterostructures

Preliminary experiments on laser annealing of ferroelectric samples by ultraviolet radiation of a KrF laser are carried out. In principle, laser annealing allows one to reduce appreciably the duration of thermal action, minimize the size of the samples treated, and control the crystallization processes in the samples. A special focussing system was employed to provide homogeneous irradiation of the spot with dimensions of ~1×1 cm² within a broad energy range from 0.1 to 10~J per pulse. The range of energy densities leading to phase transitions in thin films is determined.     

Absorption spectra of e-beam-excited Ne, Ar, and Kr, pure and in binary mixtures

A technique using the broadband emission of a laser plume as probe radiation is applied to record UV-visible (190-510 nm) absorption spectra of Ne, Ar, and Kr, pure and in binary mixtures under moderate e-beam excitation up to 1?MW/cm(3). In all the rare gases and mixtures, the absorption spectra show continuum related to Rg(2) (+) homonuclear ions [peaking at λ～285, 295, and 320 nm in Ne, Ar, and Kr(Ar/Kr), respectively] and a number of atomic lines related mainly to Rg(?)(ms) levels, where m is the lowest principal quantum number of the valence electron. In argon, a continuum related to Ar(2) (?) (λ～325?nm) is also recorded. There are also trains of narrow bands corresponding to Rg(2) (?)(npπ?(3)Π(g))←Rg(2) (?)(msσ?(3)Σ(u) (+)) transitions. All the spectral features mentioned above were reported in literature but have never been observed simultaneously. Although charge transfer to a homonuclear ion of the heavier additive is commonly believed to dominate in binary rare-gas mixtures, it is found in this study that in Ne/Kr mixture, the charge is finally transferred from the buffer gas Ne(2) (+) ion not to Kr(2) (+) but to heteronuclear NeKr(+) ion.     

Mechanisms of destruction of the partition foil of an electron gun,and methods of its protection,in the case of streamer breakdown of the discharge gap

In the practical use of electron-beam discharge lasers an important problem is that of their operating reliability. The weakest spot of an EBL is the electron-gun partition foil, and the main cause of its failure is the breakdown of the discharge gap. This paper reports investigations of the mechanisms that destroy the foil and propose for its protection a method that makes it possible to significantly increase the operating reliability of the EBL.Translated from Trudy Ordena Lenina Fizicheskogo Institute Im. P. N. Lebedeva, Vol. 116, pp. 202–208, 1980.     

A high-intensity bremsstrahlung source for investigating radiation stability of optical samples for excimer laser windows

A bremsstrahlung X-ray source (hv ≤ 600 keV) was developed on the basis of CW electron LINAC. It provides an absorbed dose rate of ∼30 Gy/s within an area of ∼2.5 cm². The radiation stability of quartz glasses and crystals for excimer lasers windows was investigated.     

Laser implantation of KTiPO4 ferroelectric nanoparticles into pores of synthetic opal placed into water

We present the results of experiments on the implantation of KTP (KTiPO₄) ferroelectric nanoparticles into pores of synthetic opal along with the data on spectral analysis of the reflection coefficients of specimens obtained. KTP powder was irradiated by an ultraviolet KrF laser in water, which increased the pore filling efficiency.     

Resonance-Enhanced Multiphoton Ionization of Molecular Oxygen at the 222 nm KrCl Laser Wavelength

Journal of Russian Laser Research - We study the photo-ionization mechanism of molecular oxygen at the 222 nm KrCl laser wavelength within a laser pulse intensity range of 108 – 1010 W/cm2,...     

Experimental investigation of radiation-gasdynamic processes that develop under the action of high-power λ=10.6 μm laser pulses on a solid in a gas

A cycle of experimental investigations was carried out on radiation-gasdynamic processes that evolve when high-power (1.5 GW) pulses from an electron-beamcontrolled CO2 laser act on a target in air or in inert gases at pressures 0.1–760 torr and flux densities 5·10⁶ to 5·10⁸ W/cm². It is shown that at pressures above several torr a laser-radiation absorption wave is produced in the gas surrounding the target and determines the evolution of the interaction. The laser-stimulated-detonation, subsonic, and supersonic radiative regimes of absorption-wave propagation in gases are investigated under conditions of planar one-dimensional geometry of the experiment and at large (up to 20 cm²) area of the irradiated spot.Translated from Trudy Ordena Lenina Fizicheskogo Instituta im. P. N. Lebedeva, Vol. 142, pp. 117–171, 1983.     

Laser implantation of sodium nitrite into artificial opal pores upon exposure of artificial opal samples to pulsed radiation of the ultraviolet laser

We present experimental results on the introduction (laser implantation) of ferroelectric NaNO₂ into artificial opal pores upon exposure of a thin powder layer of sodium nitrite applied on the artificial opal surface to radiation of the ultraviolet excimer laser. Reflection spectra of broadband radiation from the laser-implanted sample surface are compared with the reflection spectra of pure initial opals, artificial opals impregnated with a saturated aqueous solution of sodium nitrite and evaporated from solvent, and samples in which NaNO₂ was directly introduced in the form of a melt.     

Microwave energy channeling in plasma waveguides created by a high-power UV laser in the atmosphere

The grazing mode of microwave propagation in a hollow plasma waveguide formed by ionization of atmospheric air with a small easily ionized additive by strong UV pulses of the Garpun KrF laser (λ = 248 nm, the pulse duration and energy are ∼70 ns and ∼50 J) was experimentally demonstrated for the first time. The annular laser beam produced a hollow tube ∼10 cm in diameter with an electron density of ∼10¹² cm⁻³ in a plasma wall ∼1 cm thick, over whichmicrowave radiation with λ _mw ∼ 8 mm was transmitted to a distance of 60 m. Themicrowave signal transmitted by the waveguide was amplified by a factor of 6 in comparison with propagation in free space.