Sergey Babichenko

Total luminescent spectroscopy for remote laser diagnostics of natural water conditions

In undertaking the rapid diagnostics of water conditions (for organic impurities, eutrophication etc.), it is expedient to confine the effort to establishing the statistically normal state and departures from it rather than to seek the full chemical composition of the medium. What others have termed spectral signatures obtained by such methods as total luminescent spectroscopy can serve as representative indicators of both background conditions and those deviating from the normal. In this paper we show how, with the aid of laboratory catalogs of spectral signatures, it is possible to detect oil pollution at levels substantially below those of slicks (of a few microliters per liter) and to identify groups of pollutants (by remote sensing). And we describe a spectroscopic lidar we developed for marine studies.

On-line fluorescent techniques for diagnostics of water environment

An approach of on-line fluorescent analysis of organic compounds in a water is described based on multiwavelength sensing of water environment. Developed techniques are realized in remote mode to inspect large water surfaces as well as in flow-trough mode to diagnose the water quality in the pipes and open streams. The tuneable fluorescent lidars FLS-S and FLS-A for shipboard and airborne applications and compact flow-through spectrofluorimeter FLUO- IMAGER are described.

Spectral pattern recognition of controlled substances in street samples using artificial neural network system

The NarTest fluorescent technique is aimed at the detection of analyte of interest in street samples by recognition of its specific spectral patterns in 3-dimentional Spectral Fluorescent Signatures (SFS) measured with NTX2000 analyzer without chromatographic or other separation of controlled substances from a mixture with cutting agents. The illicit drugs have their own characteristic SFS features which can be used for detection and identification of narcotics, however typical street sample consists of a mixture with cutting agents: adulterants and diluents. Many of them interfere the spectral shape of SFS. The expert system based on Artificial Neural Networks (ANNs) has been developed and applied for such pattern recognition in SFS of street samples of illicit drugs.

Standoff detection: classification of biological aerosols using laser induced fluorescence (LIF) technique

The challenges of detecting hazardous biological materials are manifold: Such material has to be discriminated from other substances in various natural surroundings. The detection sensitivity should be extremely high. As living material may reproduce itself, already one single bacterium may represent a high risk. Of course, identification should be quite fast with a low false alarm rate. Up to now, there is no single technique to solve this problem. Point sensors may collect material and identify it, but the problems of fast identification and especially of appropriate positioning of local collectors are sophisticated. On the other hand, laser based standoff detection may instantaneously provide the information of some accidental spillage of material by detecting the generated thin cloud. LIF technique may classify but hardly identify the substance. A solution can be the use of LIF technique in a first step to collect primary data and – if necessary- followed by utilizing these data for an optimized positioning of point sensors. We perform studies on an open air laser test range at distances between 20 and 135 m applying LIF technique to detect and classify aerosols. In order to employ LIF capability, we use a laser source emitting two wavelengths alternatively, 280 and 355 nm, respectively. Moreover, the time dependence of fluorescence spectra is recorded by a gated intensified CCD camera. Signal processing is performed by dedicated software for spectral pattern recognition. The direct comparison of all results leads to a basic classification of the various compounds.

Real-time surveillance system for marine environment based on HLIF LiDAR

The operational monitoring of the risk areas of marine environment requires cost-effective solutions. One of the options is the use of sensor networks based on fixed installations and moving platforms (coastal boats, supply-, cargo-, and passenger vessels). Such network allows to gather environmental data in time and space with direct links to operational activities in the controlled area for further environmental risk assessment. Among many remote sensing techniques the LiDAR (Light Detection And Ranging) based on Light Induced Fluorescence (LIF) is the tool of direct assessment of water quality variations caused by chemical pollution, colored dissolved organic matter, and phytoplankton composition. The Hyperspectral LIF (HLIF) LiDAR acquires comprehensive LIF spectra and analyses them by spectral pattern recognition technique to detect and classify the substances in water remotely. Combined use of HLIF LiDARs with Real-Time Data Management System (RTDMS) provides the economically effective solution for the regular monitoring in the controlled area. OCEAN VISUALS in cooperation with LDI INNOVATION has developed Oil in Water Locator (OWL™) with RTDMS (OWL MAP™) based on HLIF LiDAR technique. This is a novel technical solution for monitoring of marine environment providing continuous unattended operations. OWL™ has been extensively tested on board of various vessels in the North Sea, Norwegian Sea, Barents Sea, Baltic Sea and Caribbean Sea. This paper describes the technology features, the results of its operational use in 2014-2017, and outlook for the technology development.

Standoff detection and classification procedure for bioorganic compounds by hyperspectral laser-induced fluorescence

The high and still increasing number of attacks by hazardous bioorganic materials makes enormous demands on their detection. A very high detection sensitivity and differentiability are essential, as well as a rapid identification with low false alarm rates. One single technology can hardly achieve this. Point sensors can collect and identify materials, but finding an appropriate position is time consuming and involves several risks. Laser based standoff detection, however, can immediately provide information on propagation and compound type of a released hazardous material. The coupling of both methods may illustrate a solution to optimize the acquisition and detection of hazardous substances. At DLR Lampoldshausen, bioorganic substances are measured, based on laser induced fluorescence (LIF), and subsequently classified. In this work, a procedure is presented, which utilizes lots of information (time-dependent spectral data, local information) and predicts the presence of hazardous substances by statistical data analysis. For that purpose, studies are carried out on a free transmission range at a distance of 22m at two different excitation wavelengths alternating between 280nm and 355 nm. Time-dependent fluorescence spectra are recorded by a gated intensified CCD camera (iCCD). An automated signal processing allows fast and deterministic data collection and a direct subsequent classification of the detected substances. The variation of the substance parameters (physical state, concentration) is included within this method.

Spectrally selective UV bactericidal effect for curative treatment of post-surgical intra-abdominal abscesses and other infections

Results of in-vitro studies of bactericidal effects of ultraviolet (UV) irradiation on strains causing drug-resistant endo-cavital infections (Enterococcus, Staphylococcus aureus, Pseudomonas aeruginosa, and others) are presented. An original technique to measure effects of UV-irradiation on bacterial growth at different wavelengths has been developed. Spectral dependences of the bactericidal effect have been observed, and spectral maxima of bactericidal efficiency have been found. Applications to curative treatments of wounds, post-surgical intra-abdominal abscesses and other diseases are discussed.

Quantitative analytical monitoring of aquatic and terrestrial targets with multiwavelength FLS lidars

The paper overviews capabilities of a multi-wavelength laser remote sensing technique in real-time analytical monitoring of aquatic and terrestrial targets. The conceptual design of the Fluorescent Lidar Spectrometer (FLS) - a compact, multipurpose analytical lidar - is described. Its modular architecture allows efficient research and routine monitoring applications from small boats or aircraft. Depending on the application requirements, the FLS analytical performance can be optimized with features such as variable excitation wavelengths and high-speed, gated hyper-spectral detection. The Spectral Fluorescent Signature (SFS) concept, which forms the background for the FLS functioning, has been successful in the detection and identification of trace organics in various environmental, industrial and other mixtures. FLS-lidars have been used in a variety of applications ranging from detecting chemical pollution in water and on soil to classifying marine dissolved organic matter (DOM) and mapping spatial distributions of phytoplankton in the Baltic, North and Norwegian seas. The presented field data obtained with shipborne and airborne FLS illustrate the approachs potential for real-time monitoring of marine, coastal and inland-water environments. Future developments are discussed.

Remote sensing of the sea by tunable multichannel lidar

Field measurements of the spatial distribution of phytoplankton by tunable lidar on board a research vessel are reported. The possibility of applying laser remote sensing to the diagnostics of hydrophysical processes in the upper layers of the sea is discussed. Twelve tracks in different directions were sensed. Marked periodical structures were observed when the vessel was moving at small angles in the direction of a swell. The frequencies of periodic structures correlated with the angle between the vessels motion and swell directions. When this angle was increased, the frequency increased proportionally. At a right angle, the periodic structures disappeared. The results do not contradict the hypothesis of the influence of internal waves on the spatial distribution of phytoplankton.