&lt;title&gt;Tunable IR differential absorption lidar for remote sensing of chemicals&lt;/title&gt;

Prasad, Coorg R.; Kabro, P.; Mathur, Savyasachee

doi:10.1117/12.366422

Cited by 8 publications

(3 citation statements)

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“…More promising standoff detection that may be able to obtain IR spectral information from a substance is photothermal spectroscopy (PTS). There is a rich history of techniques based on PTS, [4][5][6][7][8][9][10][11][12][13][14][15] which have been of interest in detecting explosives 5,8,[13][14][15][16][17][18] food and water sensors, 19 and so on. The recent advancements in coherent IR sources such as the quantum cascade laser (QCL) 20 allow delivery of well-defined tunable beams in a precise range of wavelengths where IR absorption bands of interest reside.…”

Section: Introductionmentioning

confidence: 99%

Data analysis of multi-laser standoff spectral identification of chemical and biological compounds

Farahi

Zaharov²,

Tetard

et al. 2013

SPIE Proceedings

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With the availability of tunable broadband coherent sources that emit mid-infrared radiation with well-defined beam characteristics, spectroscopies that were traditionally not practical for standoff detection 1 or for development of miniaturized infrared detectors 2, 3 have renewed interest. While obtaining compositional information for objects from a distance remains a major challenge in chemical and biological sensing, recently we demonstrated that capitalizing on mid-infrared excitation of target molecules by using quantum cascade lasers and invoking a pump probe scheme can provide spectral fingerprints of substances from a variable standoff distance. 3 However, the standoff data is typically associated with random fluctuations that can corrupt the fine spectral features and useful data. To process the data from standoff experiments toward better recognition we consider and apply two types of denoising techniques, namely, spectral analysis and Karhunen-Loeve Transform (KLT). Using these techniques, infrared spectral data have been effectively improved. The result of the analysis illustrates that KLT can be adapted as a powerful data denoising tool for the presented pump-probe infrared standoff spectroscopy.

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Section: Introductionmentioning

confidence: 99%

Data analysis of multi-laser standoff spectral identification of chemical and biological compounds

Farahi

Zaharov²,

Tetard

et al. 2013

SPIE Proceedings

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“…Differential absorption method uses two infrared laser wavelengths to detect CW agents: one corresponds to peak absorption of chemical molecule and other corresponds to weak absorption. The ratio of these two signals gives concentration of particular CW agent 12,13 . At LASTEC, the authors have been working on the project, "Development of multiwavelength LIDAR system for detection of chemical and biological warfare agents".…”

Section: Introductionmentioning

confidence: 99%

LIDAR for Detection of Chemical and Biological Warfare Agents

Veerabuthiran¹,

Razdan²

2011

DSJ

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Remote detection of chemical and biological warfare agents and toxic gases in the atmosphere is of current interest to both the military and civilian agencies. Out of all currently available techniques, no single technique provides efficient detection against such threats at significant standoff distances. Light detection and ranging (LIDAR) technologies, based on the transmission of laser pulses and analysis of the return signals, have demonstrated impressive capabilities in remote detection of such toxic chemicals. LIDAR is a highly sensitive tool to detect the extremely low concentrations of various toxic agents present in the form of thin clouds at distances of few kilometer. The detection of these toxic clouds is based on the approach of first detecting and measuring the range of the clouds using the scattering phenomena and subsequently identifying the composition of toxic clouds using absorption and fluorescence phenomena. Laser Science and Technology Centre (LASTEC), Delhi has been working on the design and development of LIDAR systems for detection of chemical and biological warfare (CBW) agents. In this paper, theoretical analysis of differential absorption LIDAR (DIAL) for detection of chemical agents and fluorescence LIDAR for detection of biological agents has been discussed. For some typical parametric conditions, the received power levels from different ranges to detect specific concentrations of chemical or biological clouds have been computed and discussed. The technical details of the indigenously developed backscattering LIDAR, which detects and measures the distance of cloud layers up to 5 km is also presented.

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“…Tunable TEA CO 2 lasers have commonly been used 1 for the detection of these toxic agents. Some of the remaining agents can be detected using tunable sources in the 2-5 m region [2][3][4] .…”

Section: Introductionmentioning

confidence: 99%

Parametric Study of Differential Absorption Lidar Systemfor Monitoring Toxic Agents in the Atmosphere

Veerabuthiran¹,

Dudeja²

2007

DSJ

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Differential absorption lidar (DIAL) techniques are advantageously used these days for detecting and monitoring traces of toxic agents located at several kilometer in the atmosphere. A theoretical study has been carried out to simulate the performance of a multiwavelength DIAL sy stem. Clouds of hy drazine, unsy mmetrical dimethy lhy drazine (UDMH), and monomethylhydrazine (MMH), located at various ranges up to 5 km in the atmosphere, have been taken as examples of the toxic agents. It has been shown that a given lidar system cannot detect any of these agents with a specific cloud thickness if the concentration of that agent is below a certain value (N min ). It has also been shown that if the concentration level of a given agent is above a certain value (N max ) at a particular distance, this value cannot be quantified for a given lidar system although the identity as well as the location of that agent can still be determined. Further, for some typical parametric conditions, the required energy levels of the laser to detect specific concentrations of these agents at different distances have been computed. Power levels of the return signals and the SNR values from different ranges have also been calculated for each of these toxic agents for a given value of the laser transmitter energy.

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<title>Tunable IR differential absorption lidar for remote sensing of chemicals</title>

Cited by 8 publications

References 0 publications

Data analysis of multi-laser standoff spectral identification of chemical and biological compounds

Data analysis of multi-laser standoff spectral identification of chemical and biological compounds

LIDAR for Detection of Chemical and Biological Warfare Agents

Parametric Study of Differential Absorption Lidar Systemfor Monitoring Toxic Agents in the Atmosphere

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