Viacheslav Meshcherinov

We present E-CAHORS—a compact mid-infrared open-path diode-laser spectrometer designed for the simultaneous measurement of carbon dioxide, methane, and water vapor concentrations in the near-surface atmospheric layer. These measurements, combined with simultaneous data from a three-dimensional anemometer, can be used to determine fluxes using the eddy-covariance method. The instrument utilizes two interband cascade lasers operating at 2.78 µm and 3.24 µm within a novel four-pass M-shaped optical cell, which provides high signal power and long-term field operation without requiring active air sampling. Two detection techniques—tunable diode laser absorption spectroscopy (TDLAS) and a simplified wavelength modulation spectroscopy (sWMS)—were implemented and evaluated. Laboratory calibration demonstrated linear responses for all gases (R² ≈ 0.999) and detection precisions at 10 Hz of 311 ppb for CO₂, 8.87 ppb for CH₄, and 788 ppb for H₂O. Field tests conducted at a grassland site near Moscow showed strong correlations (R = 0.91 for CO₂ and H₂O, R = 0.74 for CH₄) with commercial LI-COR LI-7200 and LI-7700 analyzers. The TDLAS mode demonstrated lower noise and greater stability under outdoor conditions, while sWMS provided baseline-free spectra but was more sensitive to power fluctuations. E-CAHORS combines high precision, multi-species sensing capability with low power consumption (10 W) and a compact design (4.2 kg).

Enhancement of methane emission measurement techniques is necessary to address the need for greenhouse gas emissions monitoring. Here we introduce a gas analyzer designed for remote sensing of atmospheric methane aboard unmanned aerial vehicles. This device employs the wavelength modulation spectroscopy approach and quadrature detection of laser radiation scattered from the underlying surface. Our results demonstrate that the observed correlation between various signal attributes and the distance to the surface, where laser radiation scatters, aligns with analytical expectations. Calibrations proved that the instrument provides reliable methane measurements up to 120 meters while being lightweight and power efficient. Notably, this device outperforms its competitors at altitudes exceeding 50 meters, which is safer for piloting.

The study of volatiles and the search for water are the primary objectives of the Luna-27 mission, which is planned to land on the south pole of the Moon in 2028. Here we present the tunable Diode Laser Spectrometer (DLS-L) that will be onboard the lander. The DLS-L will perform isotopic analysis of volatiles that are pyrolytically evolved from regolith. This article dives into the design of the spectrometer and the characterisation of isotopic signature retrieval. We look forward to expanding our knowledge of Lunar geochemistry by measuring D/H, 18O/17O/16O, 13C/12C ratios in situ, which could be the one-of-a-kind direct study of the lunar soil isotopy without sample contamination.

We present a concept of the Martian multichannel diode laser spectrometer (M-DLS) instrument, a part of the science payload onboard Kazachok landing platform in the framework of the ExoMars mission second stage. The instrument, a laser spectrometer operating in the mid-IR spectral range, is aimed at long-term monitoring of isotopic ratios in main Martian volatiles—carbon dioxide and water vapor—in the near-surface atmosphere. The M-DLS spectrometer utilizes the integrated cavity output spectroscopy (ICOS) technique to enhance an effective optical path length and combines high sensitivity and measurement accuracy with relatively simple and robust design. Provided proper compensation of systematic errors by data post-processing, retrievals of main isotopic ratios with relative accuracy of 1% to 3% are expected during at least one Martian year.

We propose using wavelength-modulation laser absorption spectroscopy in combination with quadrature detection of scattered light for remote industrial pollution monitoring in the atmosphere with a compact lidar-based gas sensor, which can be mounted on board an unmanned aerial vehicle. The instrument can be used for detecting leaks in product pipe lines; monitoring toxic gases near landfill sites, waste incineration plants, and other hazardous man-made facilities; analysing the gas atmosphere in industrial buildings and structures; and monitoring engineering processes at a sensitivity level of tens of ppm m in gas concentration measurements at characteristic distances of tens of metres.

Remote monitoring of industrial emissions into the atmosphere, the hazardous gases near landfills and incinerators, monitoring the presence of gas leaks in manufactures today play a huge role for human being. And this role will increase in the near future, because of aggravated ecological problems, business interests etc.We present an instrument concept for lidar monitoring of industrial atmospheric pollution, based on the commonly used technique for tunable diode laser spectroscopy (TDLS), termed wavelength modulation spectroscopy (WMS). This instrument is being developed to determine the presence of technogenic pollution of atmospheric air in concentrations that pose a danger to nature, as well as human life and health. At the first stage, methane was chosen as the object of interest.For remote measurement of atmospheric impurities, we propose to use a near-infrared diode laser (DL) operating in continuous mode with sinusoidal modulation of the injection current with a frequency of ~100 kHz. In the absence of molecules absorbing laser radiation, the photodetector detects radiation only at the modulation frequency f. In the presence of absorbing molecules, a signal appears at higher harmonics (2f, 3f). If the laser radiation is tuned to the center of the absorption line and modulated in the vicinity of this value, then the received signal at the first harmonic 1f is proportional to the total intensity of the detected radiation, and the 2f signal is proportional to the intensity absorbed by the molecules of the measured gas. Thus, the amplitude ratio of 2f signal and 1f signal characterizes the absorption of the measured gas and allows calculating of this gas concentration. Furthermore in remote measurements of laser radiation scattered from the surface, the total intensity of the detected radiation can vary by an order of magnitude, therefore, normalization of the 2f signal to the 1f signal is necessary.The correct operation of this technique require that the radiation frequency of the DL should be stabilized at the center of the absorbing line with high accuracy: ~1% of the absorption line width, which at atmospheric pressure is ~10-3 cm-1. Such high stability of the laser radiation frequency is achievable using the 3f signal, which passes through zero in the center of the line.During the implementation of the project a compact and lightweight instrument, that can be installed on the unmanned aerial vehicles (UAVs) to control the emission of harmful gases at industrial sites, landfills, will be created. Currently, such instrument using other operation algorithms have a mass of 10-20 kg and are usually installed on manned helicopters. The installation of such instrument on the UAV will greatly simplify and reduce the cost of industrial pollution monitoring. First tests of our instrument are planned on the second half of 2020. AcknowledgmentsThis work has been supported by the Russian Foundation for Basic Research [Grant No.18-29-24204].