High-efficiency, fifth-harmonic generation of a joule-level neodymium laser in a large-aperture ammonium dihydrogen phosphate crystal.

High-energy deep ultraviolet (UV) sources are required for high-density plasma diagnostics. The fifth-harmonic generation of large-aperture neodymium lasers in ammonium dihydrogen phosphate (ADP) can significantly increase UV energies due to the availability of large ADP crystals. Noncritical phase matching in ADP for (ω + 4ω) was achieved by cooling a 65 × 65-mm crystal in a two-chamber cryostat to 200 K.

Efficient selection of single high-order harmonic caused by atomic autoionizing state influence.

It is shown that the influence of atomic autoionizing states on the phase matching of high harmonic generation results in efficient selection of the single harmonic generated in the plateau region. The change of relative concentration of the atomic medium components and variation of the fundamental laser frequency can be used for tuning of the selected harmonic frequency. The possibility of achievement of contrast for the selected single harmonic of more than 10(4) at intensity conversion efficiency of approximately 10(-3) has been shown.

Third-harmonic generation in air by use of femtosecond radiation in tight-focusing conditions.

Third-harmonic generation (THG) in air in tight-focusing conditions is presented. Variation of the pulse duration supplied optimal conditions for THG by femtosecond pulses that varied in the range 110-1300 fs. We show that this third-harmonic generation was caused by Kerr-induced phase variations of fundamental and harmonic beams.

Observation of chaotic dynamics in a powerful backward-wave oscillator.

Self-modulation regimes of generation in a powerful 10-micros X-band backward-wave oscillator were studied theoretically and experimentally. The sequence of the self-modulation patterns and corresponding bifurcation values observed as the current was increased were in good agreement with the results of simulations. It was found that at a current of 120 A chaotic self-modulation set in at a power of 2 MW and a relative spectral width of 4%.

[Lipid peroxidation in patients with hypertension and renal hypertension against a background of diabetes mellitus].

Time course of changes was studied in parameters characterizing lipid peroxidation (LPO) and the total lipids counts in red cell membranes (RCM) and blood plasma (BP) of patients with hypertensive disease (HD) and arterial hypertension in chronic pyelonephritis against the background of diabetes mellitus (DM). The study groups were DM patients (group I), those with coexistent HDDM (group II), and those with arterial hypertension caused by chronic pyelonephritis in the presence of DM (group III). All three groups of patients demonstrated intensification of the cellular membrane- and blood plasma LPO as well as increase in the total lipids counts.