A collisional laser on a system of atomic levels based on the principle proposed by Gould is built for the first time. The population of the upper laser level and relaxation of the lower level occur upon inelastic collisions of excited thulium atoms with helium atoms. The lower-level relaxation occurs in a reaction with an energy defect of > 13000 cm-1.

Flashlamp design has been developed for the pumping system of the large-aperture optical amplifier used at "Luch" laser facility. Both the modernization of the mechanical units has been carried out and the proper xenon pressure in flashlamp tubes has been chosen on the results obtained from pilot flashlamps reliability tests. For 300 us pulses of discharge current at the energy loading factor of 0.25 the flashlamp lifetime exceeds 10,000 pulses.

For the first time lasing is obtained on dysprosium atomic transitions at 849.015 and 917.2 ± 0.1 nm under the pulsed gas-discharge excitation of dysprosium-helium vapors.

A thulium vapor discharge tunable laser using transitions between collision-populated upper levels was studied. Five new laser transitions were found in the 1000–1400 nm spectral range.

New lasing lines were observed in the orange (? = 589.948 nm) and near infrared (? = 1101.1 nm) parts of the spectrum on excitation of Tm vapor by a pulsed discharge. The infrared lasing lines were identified.

AbstractDie 4‐Acetylenyl‐1‐methyl‐pyrazol‐5‐carbonsäurederivate (I) bilden unabhängig von der Art des Substituenten an der Acetylen‐Gruppe bei Zugabe von katalytischen Mengen Phenylacetylenyl‐kupfer die Pyrano‐pyrazole (III).

The condensation of iodo-N-methylpyrazole-4-carboxylic acids with substituted copper acetylides proceeds with the formation of the δ-lactone ring and leads to pyrano[4,3-c]pyrazoles.

Acetylenyl-N-methylpyrazolecarboxylic acids containing an acetylenic substituent and a carboxyl group on adjacent carbon atoms cyclize in pyridine in the presence of copper phenylacetylenide to pyranopyrazoles. The same compounds are obtained by the acetylenide cyclocondensation of the appropriate iodopyrazolecarboxylic acids, but at a much lower rate.

The excitation conditions for lasing in copper vapor were optimized and a maximum efficiency of 3% was obtained.

An investigation is made of the elementary processes and characteristics of a pulsed nanosecond discharge plasma in a copper vapor–buffer gas mixture and of their correlation with the laser energy parameters. It is shown that the saturation of the stimulated emission power with rising pressure must be associated with a drop in the effective electron temperature. The complex dependence of the stimulated emission energy on the buffer gas (neon) pressure is identified and explained. It is established that at high operating pressures the pulse repetition frequency is governed by the electron cooling rate and by the plasma recombination in the afterpulse interval. At low pressures and for small laser tube apertures the pulse frequency is governed by the quenching of the metastable states by the walls. The excitation conditions are optimized and an efficiency of 2.1 % is achieved.

The lifetime of the lower active level of a decaying copper plasma laser was determined as a function of the nature and pressure of buffer gases. Pure inert (He, Ne, Ar) and molecular (CO2, H2) gases were employed. An equation for the determination of the lifetime of the lower laser level was obtained for self-terminating transitions. It was found that a collisional competition occurred between the transitions corresponding to the yellow and green lines in the spectrum.

An investigation was made of the stimulated emission mechanism and energy characteristics of an He-Mn mixture. Inelastic collisions of manganese and helium atoms were found to have a considerable influence on stimulated emission. Mixing of the upper and lower laser levels resulted in the transfer of excitation from these to the neighboring levels, which maintained the stimulated emission in the collisional regime and gave rise to a strong competition between the stimulated emission lines. This made it possible to concentrate the major part of the output radiation energy (over 70%) in the 534.1 nm line. The total output power was 3.5 W when the repetition frequency was optimal (5 kHz); the efficiency of laser action was 0.17% in a selfheated tube whose diameter was 2 cm and volume was 145 cm3.