Aleksei N. Panchenko

Effective HF(DF) lasers pumped by nonchain chemical reaction initiated by self-sustained discharge

We have studied the regimes of electric-discharge nonchain HF(DF) lasers using inductive and capacitive energy stores and determined optimum excitation conditions. On this basis, discharge-initiated HF and DF lasers have been created, which are characterized by a high specific energy output, high internal efficiency (∼10 and ∼7% of the electric input energy, respectively), and good technical efficiency (∼6 and ∼5% of the total stored energy, respectively).

Coaxial, cylindrical, and planar UV excilamps pumped by glow or barrier discharge

Design and operating parameters of powerful KrCl((lambda) approximately 222nm), XeCl((lambda) approximately 308nm) excilamps with different discharge geometry pumped by continuous glow discharges along with Ar2((lambda) approximately 126nm) and Kr2((lambda) approximately 146nm) excilamps pumped by barrier discharge are presented. Excilamps with high spatial uniformity of the output and gas lifetime up to 100 hours were developed. It was shown that efficiency of luminescence of exciplex molecules of about 30 percent can be obtained in high-voltage glow discharge and positive column of glow discharge. Output at (lambda) approximately 222nm up to 200 W from single excilamp and 500 W from three excilamps, operated in parallel, was demonstrated.

UV and VUV efficient excilamps

Operating parameters of powerful excilamps with different discharge geometry pumped by glow discharges, high-pressure volume discharge with UV-preionization and barrier discharge are presented. Intense radiation of Ar2*, Kr2*, Xe2*, ArF*, KrBr*, Cl2, KrCl*, KrF*, XeI*, XeBr*, XeCl*, XeF*, I2 and IBR molecules was obtained in rare gas or in rare gas -- F2 (CH3Br, Cl2, HCl, I2, NF3) mixtures. Excilamps with high spatial uniformity of the output, narrow emission line and high gas life-time were developed. It was shown that efficiency of luminescence of exciplex molecules KrCl* of about 30% can be obtained in high- voltage glow discharge and positive column of glow discharge. Output at (lambda) approximately 222 and 308 nm up to 200 W from single excilamp and 500 W from three excilamps operating in parallel was demonstrated. It was shown that the efficiency of barrier discharge excilamps pumped by sinusoidal pulses several tens microseconds in duration can be sufficiently improved.

High-power excimer laser systems

Two-high power excimer laser systems with square (25 × 25 cm) and circular (with a diameter of 40 cm) cross sections of the output laser beam are described. The first (second) system consists of four (five) excimer lasers. The experimental results on the generation of the high-quality high-power laser pulses are presented. Laser beams with a pulse duration of 1–250 ns, a divergence of 0.01 mrad, a spectral line width of 0.01 cm−1, and a pulse energy of up to 330 J are obtained.

High-power source of 200–350 nm spontaneous emission excited by unipolar current pulses

Spectral, energy, and temporal characteristics of pulse discharge in xenon have been experimentally studied. Upon passing from an oscillatory regime to unipolar pulses of discharge current, the power of emission in the wavelength interval 200–350 nm increases, while the emission pulse full width at half maximum (FWHM) decreases. A quartz pulsed discharge lamp excited by a generator based on high-current high-voltage diodes radiates in the 200–350 nm interval at a peak radiant intensity above 65 kW/sr and at a pulse FWHM ∼ 2 μs.

High-power HF laser pumped by an electron-beam-initiated chemical nonchain reaction

The development of a high-power HF laser pumped by a chemical nonchain reaction initiated by a radially converging electron beam is reported. A radiation energy of ∼ 115 J with an efficiency of ∼ 8% in terms of deposited energy has been achieved in a mixture with an active volume of ∼ 30 liters. It is shown that because of the high SF6 density, the total pressure jump in SF6–H2(D2) mixtures caused by the electron beam injection and the chemical reactions is several times smaller than that in the active mixtures of exciplex lasers for the same input energies. This factor considerably facilitates the development of wide-aperture HF and DF lasers with an SF6 fluorine donor pumped by an electron-beam-initiated chemical nonchain reaction.

Effect of SF{sub 6} and NF{sub 3} additives on UV and IR lasing in nitrogen

The lasing regimes of nitrogen laser on the C3Πu — B3Πg transition with a high-energy long laser pulse under pumping by a transverse discharge in N2 — SF6 (NF3) mixtures from generators with a semiconductor opening switch is studied. Laser pulses with two peaks and controlled delay between these peaks are obtained. It is shown that the time interval between the peaks may exceed 50 ns for N2 — NF3 mixtures. The conditions for obtaining effective UV lasing with a laser pulse width of more than 50 ns at the base level are determined. A possibility of depopulating the lower level of the C3Πu — B3Πg transition by induced transitions in the first positive B3Πg — A3Σu+ system is shown; this process makes it possible to expand the pulse to 100 ns at λ = 337.1 nm. The highest lasing energy and power in the IR and UV spectral ranges are obtained for nitrogen lasers with spark preionisation.

Electric-discharge high-peak-power CO{sub 2} laser

A new electric-discharge CO{sub 2} laser with a peak power of up to 45 MW and a half-height pulse duration of 50 ns is developed. The short laser pulse was formed using a generator with a semiconductor opening switch. The maximum laser radiation energy reached 6.2 J and the efficiency with respect to the stored energy was 15%. The first peak contained 70% of the energy, and the pulse duration at the base did not exceed 1 {mu}s. (lasers)

UV lasers on N{sub 2}-SF{sub 6} and N{sub 2}-NF{sub 3} mixtures pumped by transverse and longitudional discharges

Lasers on the second positive nitrogen system (the C3Πu—B3Πg electronic band, λ=337.1 and 357.7 nm) are studied. Mixtures of nitrogen with electronegative gases (SF6 and NF3) are pumped by transverse and longitudinal discharges. The amplitude—time and spectral characteristics of a laser pumped from capacitive and inductive energy storage units are measured. The output energies of the laser pumped by a transverse discharge from a capacitive and inductive storage units are 17 and 18.4 mJ, respectively. It is shown that the mean output energy in N2—NF3 mixtures continues to increase at higher pulse repetition rates than in nitrogen. Under the pumping by a transverse discharge, two-peak 357.7-nm lasing with a total pulse duration of >40 ns is achieved. It is established that adding SF6 to the mixture enhances the output power of a longitudinal-discharge-pumped nitrogen laser.

Efficient electric-discharge CO2 laser with a prepulse formed by a generator with an inductive energy storage device

Results are presented of experimental investigations of a CO2 laser pumped by a self-sustained discharge from a generator with an inductive energy storage device and a semiconductor current chopper. It is shown that the energy stored in the inductance of the discharge circuit can form a prepulse capable of depositing most of the energy in the active mixture for nearoptimum values of the parameter E/p. A radiation energy of 3 J was achieved in an electricdischarge laser with a 0.181 liter active volume with a 17% efficiency relative to the energy stored in the capacitive storage device.