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The spectral characteristics of high harmonic generation are studied by applying Xe–He mixture gas cell. The cutoff position of harmonics in mixed gases is extended from the 21st to the 27th. In addition, we found the destructive interference of harmonics in Xe–He mixture.

The mathematical model of the XeF(C–A) amplifier of hybrid laser system THL-100 was developed. The numerical investigations of spatial distribution of small-signal gain coefficient in active medium were carried out. The effect of the mirrors reflection coefficient, pumping power, and input pulse energy on the output energy was investigated. It is shown that at input pulse energy of 20 mJ and a mirror reflection coefficient of 0.995 it is possible to increase the output energy up to 3.5 J.

Spectral-luminescent and lasing properties of chromene 3 (CAS No. 52372-39-1) and chromene 13 (CAS No. 52372-36-8) in solutions and solid matrices are investigated. The regularities of their changes depended on the molecular structure and intermolecular interactions have been studied. It is shown that the fluorescence quantum yields of the studied compounds are high (0.9%). The studied compounds emit in red spectral range in solutions, films and matrices of PMMA (> 600 nm). The lasing efficiency of solid active media based on chromene 3 pumped by the second harmonic of YAG-Nd³⁺ in transverse pumping reaches 45%. Operating lifetime is comparable to the best-known organic solid state active media that emit in the red spectral range (over 30,000 pulses at one point at decreased efficiency by 5–10%). For chromene 13 lasing efficiency in solutions and matrices is lower (28% and 21%), operating lifetime of the solid active medium is high. The possibility of obtaining the generation of the compounds in thin films was studied.

Results of studying and designing an excitation pulse generator with magnetic compression of pulses by saturated choke for pumping active media of CuBr, Sr, and Ca vapor lasers are presented. A power IGBT transistor is used as a commutator. The generator makes it possible to operate at an excitation pulse repetition frequency of up to 20 kHz. The total average power at all generation lines in a CuBr laser with pumping from this generator is of about 6.0 W; in Sr and Ca lasers, of about 1.3–1.7 W.

This paper presents the algorithm for processing the images obtained by a laser monitor, which makes possible to get data on the observed object or its separate parts. The macros is designed in MATLAB environment implementing this algorithm, and its testing at different objects is carried out. It has been shown that for linear object displacement with the measurement pitch from 10 to 500 micron the error does not exceed 5 percent.

The paper repots on experimental and theoretical research in the effect of chlorine concentration on the radiation efficiency of a coaxial dielectric barrier discharge Xe–Cl ₂ excilamp at a working mixture pressure of 240–250 Torr. The experiments were performed in the range of Cl ₂ concentrations 0.01–1%. The characteristics of the barrier discharge were calculated in the framework of a one-dimensional magnetohydrodynamic model in the range of Cl ₂ concentrations 0.1–5%. It is shown that at a chlorine concentration of 0.01–0.1%, the radiation intensities of the Xe₂* band (172 nm) and XeCl* band (308 nm) are comparable. As the Cl₂ concentration in the mixture is increased, the radiation intensity of Xe₂ decreases rapidly, and at a chlorine concentration of ≥ 0.2%, the radiant flux of the discharge is dominated by the XeCl (B → X) band with a maximum intensity at 308 nm. The maximum radiation efficiency of this band is attained at chlorine concentrations of 0.4–0.5%. The numerical simulation shows that the total power deposited in the discharge increases with the chlorine concentration due to the increase in the power expended in the heating of positive and negative ions. The power dissipated by electrons decreases as the chlorine concentration in the working mixtures is increased. Recommendations are given on choosing the chlorine content in the mixture to decrease the VUV radiation intensity of the second Xe₂* excimer continuum with a little decrease in excilamp efficiency.

This work is dedicated to the urgent issue of developing a method system of integration experimental devices and software for altitudinal polarization lidar, used in investigation of the microstructure of clouds in the upper layer. The information on characteristics of the investigated medium is contained in the lidar signal, which is a pulse of a complex form with duration of several tens of microseconds.

The peculiarities of processing of the reconstructed holographic images of plankton particles are considered in the paper. The necessity of investigation of the particles appears in the challenges of hydrobiology, hydroacoustics, and oceanic optics. Method of plankton particles recognition with the accuracy up to species on example of the plankton species Episсhura Baicalensis is suggested. The results of approbation of the method are presented, based on video sequences configured from holographic data and visualizing the particles movement dynamics.

Measurement results of the chlorophyll fluorescence spectra excited by tunable radiation of first and second harmonic of Ti:Sapphire laser are presented. The efficiency of fluorescence excitation is investigated depending on laser radiation wavelength.

The technique of passive space infrared and microwave atmospheric sounding is discussed. A result of analysis of the sounding is discovery of tropospheric inner gravity waves (IGW). It is possible to investigate now the infrasonic IGW with frequency of 4 × 10^–5 Hz or less. A wave, looking like mirror of IGW, is found in the initial part of the tropopause, the wave is named mirror wave (MW). MW origin is discussed, a simulation of IGW and MW is realized. The meteorologic events, explosives and seismic activity may excite IGW and MW. Diagrams of IGW and MW during the Japan catastrophic earthquake of 2011 are shown. The before-earthquake region with large seismic activity is found.