The progression of high-power laser systems gave rise to several concepts of their advent. There are laser systems in which the population inversion is made by thermal pumping (gasdynamic lasers), by chemical reactions (chemical lasers) and by electrical discharge (electric-discharge lasers) or by using their combination. To maintain high-power radiation in the continuous regime, gas flow is used in all lasers. Among there is also idea of creation of electrogasdynamic CO combustion-product laser in using air as buffer gas with demonstrating lasing on the small-scale model system. A multipurpose self-contained laser system of high power with electrogasdynamic CO combustion-product lasers are proposed. For economical and ecological reasons the gasdynamic and chemical lasers are practically unacceptable in industrial applications. Therefore, the proposed electrogasdynamic CO laser is preferable. Determination of efficiency of high- power laser in the industry and optimization its parameters require the formation of particular task. However, at the present time high-power lasers expect only the fields of their application. Widespread use of high-power lasers in the industry is impossible because of limits of existing in high-power lasers, high cost of laser energy production and laser itself. The object of this work is a design of general conception of creating high-power industrial lasers by generalizing results of works. It is allowed to define the ways of their advent and the fields of application and to solve the problem of high-power industrial laser's creation. This problem arose in appearing first lasers. In this case, the fields of application, which are required small powers, are not considered. For example, holography, survey, communications, medicine, etc., do not impose high requirements to power quantity and laser efficiency.

Generation performances of the multikilowatt cw CO₂ laser with unstable resonator and output variable reflectivity mirror (VRM) have been investigated depending on the resonator magnification, aperture of the diaphragms restricting the laser beam in the resonator and the VRM parameters such as reflectivity and profile of the reflecting zone. A possibility of good matching of the parameters of optical resonator and the gas-discharge chamber of the laser was shown both theoretically and experimentally. The beam divergence three times better than that of the stable resonator has been achieved at decreasing the generation power only by 15%.

The paper describes bimorph mirrors purposed for operation in industrial laser machines. A detailed study of the technical parameters of cooled single channel deformable mirrors has been carried out. Results are given of preliminary tests of the uncooled bimorph mirrors in CO₂ industrial laser machine with output radiation power exceeding 2 kW as well as in the laser machine using a pulsed copper vapor laser with mean radiation power of 35 W.

The luminescent method and the method of double-beam shear interferometry were used to measure the spatial and temporary characteristics of density fluctuations of the turbulent flow in the CO₂ laser tube with fast-axial flow under the conditions of dc discharge. The amplitude dependence of the small-scale optical nonuniformities of the laser mixture on the discharge input has been determined. The analysis of influence of the thermo-ionized instability of the discharge on the small-scale nonuniformities of gas density has been carried out. The method of frequency selection of the registered signal has been used for selection of a turbulent component of the gas-density fluctuations.

A 40 MHz RF discharge excited planar cw CO2 laser with the near diffraction limited output power up to 50 W and the efficiency of 8.5% is studied. Two schemes of the hybrid resonators as positive, as negative branches of the stability diagram are used. The output power and spatial characteristics of the laser beam are studied for both the resonator cavities.

The review of experimental and theoretical investigations carried out in VNIIF during about 25 years and devoted to the problems of nuclear-pumped lasers is presented.

The results are presented of experimental and theoretical investigations of excitation and generation of the HF laser pumped by nonchain chemical reaction initiated by a beam of electrons as well as of the KrF and XeCl lasers pumped by beams of electrons. The effect of the volume charge field on the distribution of energy over the cross section of a laser cell and of the radiant energy density over the cross section of an output laser beam in mixtures with different concentrations of halogen is analyzed. The output energy density distribution over the beam cross section for lasers excited by the radially convergent beam of electrons and the total pump energy are determined. The pump energy distribution over the laser cell cross section and the total pump energy in various gas mixtures are calculated.

The closed equations system for determination the intensity of the longitudinal electric field, electronic temperature and the temperature of the working gas that are stated in plasma of gas discharge of the one-component gas mixture in the case of diffusion regime of the discharge burning is obtained. The dependences of these gas discharge's internal parameters in helium on the discharge current value, gas pressure and the size of the working cappilar radius and also the dependence on the temperature of the external walls of the gas discharge tube are investigated.

Experimental results of scale modeling of crossed flute cavities developed for applications in high power free electron lasers are described for the eight millimeter wave range. Intense optical cavity modes were excited having ring distribution on the cavity mirrors and focused distribution in the center of the cavity between the mirrors.

It has been established, that the surface destruction has 3 stages: breakdown origin (the distance is 3 - 5 mm from the surface timed up to 1 microsecond(s) regarding leading edge of laser pulse); evaporation (timed for 3 - 5 microsecond(s) ); interaction of the adsorbents with plasma torch and laser radiation, heating and cracking under the influence of UF plasma radiation.

Numerical and experimental investigation on dependence of the output power P and radiation efficiency (epsilon) from the active medium composition and resonator characteristics was performed for an overtone supersonic cw HF laser. The optimal parameters of the active medium and of the dichroic mirrors for the device with the nozzle array length L equals 40...150 cm were determined. We obtained P approximately equals 8 kW and (epsilon) equals 43% in the experiment by L equals 70 cm. It has been established that the dichroic mirrors operated with a shot life time by energy density of 93 kW(DOT)cm^-2.

It is proposed the short-wavelength high-gain Cherenkov oscillator driven by supercurrent. In this concept, thin superconductor film, carrying dc current, is situated within a slow-wave structure (dielectric superlattice in a waveguide). It is shown that an amplification of the electromagnetic wave is possible when the wave phase velocity is close to the characteristic diffusion velocity of the order parameter phase. The small-signal exponential gain coefficient is calculated. Estimates show the proposed scheme be promising source of coherent THz radiation.

A new concept of the optical oscillator driven by low- voltage high current electron beam is discussed. The amplification effect is based on the dissipative instability of electron beam near the surface of resonant absorbing material.

As a result of the theoretical research the possibility to control the laser pulse length of the chemical HF/DF laser in a range from the part up to some hundreds of microseconds by means of the variation of the laser medium density and the photoinitiation intensity by two orders of magnitude is shown. At that the specific energy characteristics of the active medium does not change essentially because of the variation of the chemical chain length under necessary condition of using the high-quality optical resonator. The calculations have shown that the specific output energy varies from 100 up to 300 J/g and the physical efficiency from 2,000 up to 18,000%. The laser pulses with length from 2 up to 45 microsecond(s) are obtained in experiment for HF and DF laser with the technical efficiency of 10 - 50%, the pulse energy from 2.6 down to 0.1 kJ, the specific energy from 88 J/g (50 J/l) down to 10 J/g (2 J/l) without the fulfillment of the complete optimization. In experiment the mode of the high frequency radiation pulsation is registered with the length of a separate peak lesser than 10 ns and the period equal to the double time of the photon pass through the resonator.

The compact sealed-off RF-self-excited slab CO₂ laser has been developed. The average output power in pulse- repetitive mode of operation is controlled in the range of 20 - 200 W. The maximum pulsed power exceeds 400 W. The divergence of laser radiation is close to diffraction limit. The weight of the laser-head and RF-power supply is in total 40 kg.

Variable reflectivity output mirrors (VRM) provide good possibility for output coupling of diffraction limited beams both from gas and solid state laser media. A set of different VRM resonators was designed and tested in fast- transverse and fast-axial-flow CO₂ lasers. It was shown that the phase profile of the output beam in VRM resonator may be improved by the appropriate design of the VRM output coupler. The results of experimental and theoretical studies of stable and unstable VRM resonators operation in CW CO₂ lasers with output power up to 3 kW are presented.

We performed the analyze of principles of wide-band VO₂- mirrors creation for mid-IR (2.5 - 12 micrometers ) laser radiation control. It was shown, that the choice of interference system of VO₂-mirror makes possible to extend region of maximum reflection change up to 1 - 2 (mu) . Calculations and experimental results are presented for mirrors with dR/d>0 and <0 with the change of reflection coefficient from 0.1 up to 94 - 98%.

A broadband, tunable, scanning IR-range etalon for FEL applications was designed, developed and tested. The design details and the results of the experimental tests are described and discussed.

Using experiment data of laser damage threshold for ZnGeP₂ surface we have made calculations of dependence of different frequency generation efficiency from nonlinear crystal length for different values of sum laser intensity (up to 10 GW/cm²) corresponding to definite CO₂ laser types. Computation results showed that more 1-MW submillimeter power values are possible if to use sufficiently short powerful pump. These pulses are of considerable interest for many applications in matter investigations. Also we suggest to generate powerful laser half-cycle pulse at submillimeter wave region by means of difference frequency generation with ZnGeP₂ and by converted radiation reflection and absorption switch on semiconductor wafers.