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The results of long-term research on the optimization of technological processes for obtaining crystals with high optical quality that meets the requirements of mass production of nonlinear optical elements are presented. The physical nature of the defects that determine the optical losses of nonlinear optical ZnGeP₂ crystals is clarified. Methods and modes of effective post-post processing of single crystals that provide an increase in optical quality are proposed. Precision thermal equipment has been developed for the synthesis of multicomponent compounds and the growth of crystals with controlled properties. The conducted research cycle allowed us to obtain crystals with record absorption coefficients and breakdown thresholds. The dispersion properties of single crystals are investigated. The conditions for phase matching and conversion efficiency of laser pulses of various durations and wavelengths are calculated. Based on the calculations performed, nonlinear optical elements were manufactured, which were used in numerous experiments on the conversion of the frequency of laser radiation. The results of some experiments on frequency conversion in ZnGeP₂ crystals, which were also used in atmospheric trace gas analysis systems, are briefly presented.

An original method for objective climate classification is being developed based on the idea of the universality of the principle of consistency of natural and climatic processes. The method makes it possible to study the response of the climate system structure to different external factors taking into account regional characteristics. A unique interactive software package created for this task allows one to select, study, and simulate climatic clusters based on the climatic characteristics of any nature on any spatial and temporal scales. Examples of the method implementation are given.

A scheme of the new stage of the development of a generalized empirical model of optical characteristics of tropospheric aerosol in Western Siberia is described. An algorithm is suggested for accounting the particle size distribution function of absorbing matter and the condensation activity of aerosols. Optical characteristics have been calculated with the complex refractive index of particles of different sizes variable with the relative air humidity. Using the “haze” type of the “aerosol weather” as an example, the results of model calculation are compared with the average experimental data on the angular scattering coefficient in a small-angle range and the spectral behavior of the aerosol extinction coefficients.

The review provides information on ozone concentration in the surface air layer in the second half of 2020. Data were obtained at 13 stations located in different regions of Russia. An assessment was made of the excess of hygienic standards established in the Russian Federation, both in the second half of the year and in the whole 2020. It is shown that the daily average maximum permissible concentration of ozone is regularly exceeded at all stations. There are cases of exceeding the one-time maximal maximum permissible concentration.

High sensitivity spectra of the main ozone isotopologue were recorded using a cavity ring-down spectrometer in the region 7920-8670 cm^-1 covering the range up to the dissociation threshold and above. The sensitivity on the order 2 × 10^-11 cm^-1 was achieved. This makes it possible to detect high energy combination bands up to ten vibrational quanta in the electronic ground state. Line positions and intensities are measured for these bands. Vibronic hot bands of the ¹⁶O₃ borned by transitions from the (100) and (020) electronic ground state levels to the excited ³ A ₂ triplet state were recorded for the first time providing new information about the dependence of predissociation broadening on rotational quantum numbers.

The effect of restrictions caused by COVID-19 pandemic in Novosibirsk in spring 2020 on the composition of trace atmospheric gases and organic aerosol in the air of Novosibirsk Akademgorodok is investigated. The concentrations of aldehydes (formaldehyde, acetaldehyde, benzaldehyde, acrolein, and substituted aromatic aldehydes), the corresponding carboxylic acids, and peroxy compounds were studied before and after adoption of restrictions, prior to the start of vegetation period, that is, with the minimal emission of biogenic compounds into the atmosphere. Differences in diurnal variations and the composition of hydroperoxides are revealed at the background of weakening of anthropogenic sources. The role of hydroperoxides in gas-to-particle conversion is shown. In parallel, the concentrations of nanometer-sized aerosol particles were measured, and differences in their chemical composition are analyzed. To explain the observed changes in the composition of organic aerosol, numerical simulation of the stages leading to the formation of condensable products was carried out. A sharp decrease in the strength of anthropogenic sources allowed us to reveal and characterize the contribution from biogenic sources into the formation of organic atmospheric aerosol and to describe this process.

Algorithms for real time two-dimensional digital image processing when observing on atmospheric paths are considered. A procedure for measuring the turbulence parameter directly during of observation is suggested. It can be applied both with the use of a reference object (a radial mire), and without it. An efficient high-speed correlation tracking algorithm with reference frame normalization was applied to correct the image jitter caused by the atmosphere. Blurred image restoration algorithms based on the inverse filterization of angular spatial frequencies are implemented with the use of parallel computing procedures from the Intel® MKL and IPP libraries. The results of computer simulation of digital images blur and its correction are presented, as well as examples of processing experimental video frames on real atmospheric paths.

The optical scheme and technical characteristics are described of an experimental setup for atmospheric studies of a possibility of compensating for aberrations of the initial wavefront of an optical beam by the aperture sensing technique based on the signal of atmospheric backscatter of radiation from an additional laser source.

The results are presented of experimental studies of a possibility of compensating aberrations of the initial wavefront of an optical beam by the aperture based on the atmospheric backscatter signal of radiation from an additional laser source at a different wavelength. It is shown that the makes it possible to reduce the beam wavefront aberrations by several times, down to 1-2 wavelengths at optimal angles of view of the scattered radiation receiver. As a result, the distortions of the intensity distribution in a beam cross section and beam divergence decrease and the power in the beam paraxial region increases.

Theoretical aspects of nonlinear propagation in air under filamentation of high-power ultrashort laser radiation with coronalike transverse intensity distribution are theoretically considered. A coronal intensity profile is assumed to be formed by incoherent superposition of several emitting sub-apertures arranged into a ring. Using the numerical solution to the time-averaged nonlinear Schrödinger equation, the transformations along an optical path of the intensity profile of the synthesized beams by varying the number and power of the partial emitters composing them are investigated. We show that the synthesized beams of coronal profile have a number of advantages from the point of view of control over the filamentation region. Particularly, by changing the number and geometric size of the individual subapertures it is possible to significantly delay the beginning of filamentation of the whole beam and increase the distance of its existence in comparison with beams of traditional unimodal profile (Gaussian, plateau-shaped).