Home – Home – Jornals – Atmospheric and Oceanic Optics 2026 number 4

В сентябре 2025 г. в Томском Академгородке прошла Международная конференция по импульсным лазерам и применениям лазеров (AMPL). Она проводится раз в два года в третью неделю сентября и в прошлом году собрался в семнадцатый раз. Тематика Конференции была традиционной. Участники представили устные и стендовые доклады, посвященные фундаментальным вопросам лазерной физики, физическим и химическим процессам в активных средах лазеров, новым активным средам, новым типам лазеров и лазерных систем, применению лазеров в науке, производстве, локации, медицине и других областях деятельности, проблемам вывода новых лазерных устройств и технологий на рынок, а также созданию и применению источников спонтанного излучения и использованию углеродных материалов. В организации биеннале приняли участие Институт оптики атмосферы СО РАН (г. Томск), Институт сильноточной электроники СО РАН (г. Томск). Впервые к подготовке мероприятия присоединился Институт физических наук Китайской академии наук (ИФН КАН) (г. Хэфэй, Китай), что подчеркивает международный характер конференции.

Natural water contains dissolved organic matter (DOM), which plays an important role in biogeochemical processes and affects the functioning of aquatic ecosystems. The paper analyzes the spectral and luminescent characteristics (optical indices, difference absorption spectra, fluorescence quantum yield, and protein-like fluorescence) of DOM chromophoric fraction (CDOM) in two meromictic reservoirs on the coast of the Kandalaksha Bay of the White Sea, lakes Elovoe and Trekhtzvetnoe based on the results of expeditionary work in 2025. The difference in optical indices in different layers of the reservoirs (the surface fresh layer, the intermediate brackish aerobic layer, the chemocline, and saline bottom hydrogen sulfide zone) and their relationship with hydrochemical parameters are shown. An increase in the quantum yield of CDOM fluorescence in the chemocline of the Lake Elovoe and its decrease in the Lake Trekhtzvetnoe are explained. The results are of importance for ecological monitoring of aquatic ecosystems, as well as for understanding the processes that influence optical characteristics of natural CDOM.

Expanding the instrumental and analytical methods for identifying harmful impurities in the atmosphere is an important task for solving environmental problems. In this regard, the work focuses on developing a comprehensive approach to detection of harmful impurities in atmospheric air. This approach is based on measurements of the absorption spectra of air containing harmful impurities along a path by pulse terahertz spectroscopy methods. To analyze the obtained spectral data, a neural network is created and applied, and arrays of model absorption spectra of gas mixtures with different qualitative and quantitative compositions are generated for its training. It is shown that the neural network is capable of identifying six gas components in concentrations of up to 0.01 ppm with accuracy of 90-95%. A series of experiments with real gases confirms the sensitivity of the THz spectroscopy method to low gas concentrations in the mixture. The results show that the combined method is sufficiently sensitive for identifying both single gases and gas mixtures, which can be used for environmental monitoring.

Plant protection measures against various pathogens must be implemented in a specific period of time to avoid potential economic losses. Objective and reliable automated plant health diagnostics requires new approaches and their integration into traditional monitoring and assessment systems. This paper describes an experimental setup that detects elevated levels of plant stress hormones in air due to mechanical damage from direct atmospheric absorption of radiation based on Fourier transform infrared spectroscopy. The results of this study, on the one hand, open the possibility of detecting plant stress by analyzing the atmospheric absorption spectrum above a plantation, and on the other hand, they identify a wide range of fundamental problems, the solution of which will lead to the development of an effective method for remote diagnostics of plant health.

In natural and artificial water bodies, photolysis is the primary process that determines the transformation and fate of many pharmaceuticals. However, there is a lack of information on the degradation products of sulfonamide antibiotics and their toxicity. Phenols are potential transformation products of pharmaceutical contaminants and pose a threat to human health. This paper presents the results of an experimental study of the phototransformation of sulfamethoxazole in water. The irradiation experiments were carried out in a stationary photoreactor using KrCl (222 nm), XeBr (282 nm), and XeCl (308 nm) lamps and a bactericidal irradiator UVb-04 (180-275 nm) as sources of UV radiation. To determine the total phenol content in the photoproducts of sulfamethoxazole, a colorimetric method with Folin-Ciocalteu reagent was used. The changes observed in the absorption and fluorescence spectra after irradiation of aqueous sulfanilamide solutions are described in detail. The formation of three fluorescent photoproducts is shown, one of which is stable and accumulates in the solution regardless of the selected UV radiation source. The total phenol content increased after UV irradiation. It has been established that after 128 min of exposure to a KrCl excimer lamp, the total phenol content is 4 times higher than the initial value and amounts to 331.89 mg GAE/g. The results can be of interest for studying the degradation mechanism of sulfonamides, identifying toxic degradation products, and evaluating their antioxidant activity.

Phenol enters the environment during the combustion of plants and biomass, as well as through anthropogenic emissions. Phenolic compounds can act as precursors to organic aerosols, adversely affects human health, and reduces atmospheric visibility. The static absorption spectra of phenol and its volatile substituted compounds ( p-cresol and vanillin) presented in this work were obtained and analyzed using computer simulations based on quantum-mechanical molecular dynamics. The optical spectra were averaged over excited instantaneous molecular conformers fluctuating along system's evolution trajectories. The photodynamic dissipation of electronically excited states of the molecules was studied by generating trajectories in nonadiabatic molecular dynamics. Changes in the electronic structure of phenol, p-cresol, and vanillin, along with the crossing points and dissociation of potential energy surfaces, were obtained using the mixed-reference spin-flip approach within the time-dependent density functional theory. The O-H bond breaking in the hydroxyl group followed by deprotonation causes minor structural deformations for the molecules under study. It is shown that, upon excitation, the dissociation of the hydroxyl group occurs via an electronic transition to the σ-MO localized on the elongated O-H bond.

The paper presents the results of using carbon dots as luminescent nanosensors of heavy metal ions in aqueous media. The application of machine learning methods to the photoluminescence spectra of nanoparticles in multicomponent aqueous salt solutions made it possible to simultaneously determine the concentrations of desired substances. The comparative analysis of the quality of solving the inverse problem by different neural networks was carried out. Comparison of the results of using neural networks and X-ray fluorescence analysis for determining the ionic composition of industrial process media showed that the accuracy of the developed nanosensor fully meets the requirements for monitoring and controlling the composition of waste and process water.

Properties of high-altitude discharges in the atmosphere of the Earth and other planets and their satellites are actively studied in past three decades due to the acquisition of new data, primarily because of improvement of optical observation methods. This work experimentally and theoretically studies the ratios W₁₊/W₂₊ of radiation energy spectral density of four bands of the 1st positive nitrogen system (1+) to a band of the 2nd positive nitrogen system (2+) with a wavelength of 337 nm. The ratios are compared for atmospheric air and nitrogen with low impurity content at pressures of 0.04-0.4 torr. It is shown that the quenching rate of C³Π_u triplet states of molecular nitrogen increases in a nitrogen-oxygen mixture, which decreases the ratios W₁₊/W₂₊. It is confirmed that quenching of B³Π_g state by nitrogen and oxygen molecules increases with the air density in the Earth's atmosphere. The results can be useful for studying physical processes occurring against the background of the interaction of high-energy electrons with gases in the atmospheres of a number of planets and their satellites, which predominantly contain nitrogen.

Sources of short-wavelength radiation generated by the interaction of high-intensity radiation with matter are in demand for experimental research in physics, chemistry, and biology. Reproducible parameters of the generated short-wavelength pulses require the use of femtosecond pulses with stabilized carrier-envelope phase (CEP). The work is devoted to the study of the effect of pulse envelope noise on the error in determining the CEP. For the CEP stabilization system based on f-2f interferometer with spectral interference pattern resolution, it is shown that an increase in noise of an original pulse increases the error in determining CEP from supercontinuum radiation, which attains about 100 mrad at an envelope noise of 1%. An increase in the radiation peak power increases the influence of noise on the error in determining CEP due to supercontinuum generation. The results can be used to develop and optimize systems for measuring the femtosecond pulses carrier-envelope phase with pulse repetition rates in kilohertz range.

Improving the frequency-energy characteristics of lasers is an important task associated with both fundamental problems and the implementation of new engineering solutions. Increasing the pulse repetition rate of active media based on metal vapor, in particular a manganese atom, is necessary for the creation of high-speed laser monitors. This paper analyzes radiation spectral characteristics of an active element based on manganese atom transitions excited by a high-frequency semiconductor source based on the LTD generator concept. Radiation with an average power of 250 mW, including visible and IR components, was recorded at a pulse repetition rate of 75 kHz. It was experimentally established that the visible component disappears at frequencies above 75 kHz, which had not been previously observed. At a pulse repetition rate of 125 kHz, the average radiation power was 200 mW. In the IR region, the largest contribution (> 50%) comes from radiation at a wavelength of 1291.37 nm. The results of the work can be used in visual-optical diagnostics of various processes in laser monitor.

The development of laser radiation sources in the yellow-red spectral region with an extended range of adjustable generation parameters is a relevant and sought-after task in biomedical applications. This work experimentally studies spectral, temporal, spatial, and energy characteristics of neon atom radiation excited by a pulsed inductive cylindrical discharge. Lasing was obtained at 3 p → 3 s transitions of neutral neon atoms with wavelengths of 594.4 nm and 614.3 nm. The intensity ratio of these spectral components I ₅₉₄ : I ₆₁₄ depended on the pumping conditions and varied from 1 : 1 at pressures of 0.2-0.3 torr to 1 : (2...4) at an optimal pressure of about 0.13 torr. A maximal lasing energy of 17 μJ was achieved at a charging voltage of 29 kV (limited by the excitation system characteristics). A decrease in charging voltage below 20 kV resulted in the breakdown of lasing. The study of the temporal lasing characteristics revealed that lasing at the both wavelengths began simultaneously. The pulse duration was identical and attained an average of 12.5 ± 0.5 ns (FWHM), which corresponded to a pulse power of over 1.4 kW. These results can be used to develop gas-discharge lasers with tunable radiation parameters for ophthalmic applications.

A gas discharge is an effective converter of electrical energy into optical radiation. The mechanisms of current development and the quantitative contribution of electron multiplication and emission processes remain undetermined, even in the simplest discharge types, such as the abnormal glow discharge. In this work, the current-voltage characteristics and the voltage distribution in the cathode sheath region of a DC discharge in helium were investigated in the pressure range 3.5-9 torr and the voltage range 200-1700 V. The non-monotonic behavior of the current-voltage characteristics was demonstrated under conditions minimizing controlled and uncontrolled impurities. It was shown that at powers deposited into the discharge exceeding 3.5 W, a deviation from the asymptotic approximation of the cathode fall length to a value of 0.37 of the normal length is observed, which is associated with a change in particle concentration in the near-cathode region. The derived empirical law made it possible to refine known approximations for the dependence of temperature and particle concentration on the power deposited into the discharge, which is relevant for description of the kinetics of processes in high-voltage gas discharges used as sources of optical radiation.

One of the fundamental directions in the development of lasers based on self-terminating transitions (RM transitions) in metal atoms and ions is their application in brightness amplification systems. Improving such systems requires expanding the operational spectral range and increasing the pulse repetition frequency. A promising approach to addressing these challenges is the use of a new class of high-speed high-frequency switches based on a slit discharge (eptrons) for pumping RM lasers, particularly those operating in the UV range. Within the framework of this approach, this paper studies the frequency-energy characteristics of a mercury ion RM laser (λ = 398.4 nm). The use of a high-speed slit-discharge switch made it possible to generate voltage pulses with a rise time of 2-3 ns across the electrodes of a gas-discharge tube and achieve lasing in a double-pulse mode at repetition frequencies up to 300 kHz.It was determined that the laser pulse energy strongly depends on temperature and repetition frequency, with the optimal frequency decreasing as the temperature increases. Lasing in the form of bursts consisting of four pulses has been demonstrated. The achieved high pulse repetition frequencies of the laser radiation along with its short wavelength can contribute to the creation of unique brightness amplification systems based on the Hg⁺ RM laser.

The dynamics and spatial distribution of atmospheric pressure glow discharge plasma radiation in an argon flow in the plasma generation mode with metal particles is studied. The discharge system consisted of two symmetrical tantalum crucible-electrodes with inserts of a low-melting metal (magnesium) and operated at a current of 100-600 mA, a relatively high discharge voltage of 150 to 200 V, and an argon flow rate of 1-3 L/min, without changing to spark or arc discharge modes. Such parameters ensured the stable generation of magnesium atom fluxes in the discharge plasma, resulting from discharge initiation in the presence of afterglow from the decaying plasma in the interelectrode gap. It is shown that the most intense emission from metal atoms is observed near the electrode which acts as a cathode of the glow discharge during a given pulse half-period. The results of this work are of interest to researchers engaged in aerosol flux generation, synthesis of nanostructured materials, and the application of gas discharge for optical emission generation.