Mobile spectroscopic system for trace gas detection using a tunable mid-IR laser

Vaicikauskas, V.; Kaucikas, Marius; Švedas, Vitas; Kuprionis, Z.

doi:10.1063/1.2668940

Cited by 13 publications

(7 citation statements)

References 12 publications

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“…For stand-off detection of vapor phase chemicals, published detection limits vary greatly depending on the detection scenario and the absorption cross-section of the chemical of interest 3,5,9,10,11,12,13 . In general, the larger absorption cross-sections found in the shortwave-and longwave-infrared regions (3-5 µm, SWIR and 8-12 µm, LWIR) provide higher sensitivity than the near-infrared (1-2 µm).…”

Section: Current Instrumentationmentioning

confidence: 99%

High sensitivity stand-off detection and quantification of chemical mixtures using an active coherent laser spectrometer (ACLaS)

Macleod

Weidmann

2016

SPIE Proceedings

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High sensitivity detection, identification and quantification of chemicals in a stand-off configuration is a highly sought after capability across the security and defense sector. Specific applications include assessing the presence of explosive related materials, poisonous or toxic chemical agents, and narcotics.Real world field deployment of an operational stand-off system is challenging due to stringent requirements: high detection sensitivity, stand-off ranges from centimeters to hundreds of meters, eye-safe invisible light, near real-time response and a wide chemical versatility encompassing both vapor and condensed phase chemicals. Additionally, field deployment requires a compact, rugged, power efficient, and cost-effective design.To address these demanding requirements, we have developed the concept of Active Coherent Laser Spectrometer (ACLaS), which can be also described as a middle infrared hyperspectral coherent lidar. Combined with robust spectral unmixing algorithms, inherited from retrievals of information from high-resolution spectral data generated by satellitebased spectrometers, ACLaS has been demonstrated to fulfil the above-mentioned needs.ACLaS prototypes have been so far developed using quantum cascade lasers (QCL) and interband cascade lasers (ICL) to exploit the fast frequency tuning capability of these solid state sources. Using distributed feedback (DFB) QCL, demonstration and performance analysis were carried out on narrow-band absorbing chemicals (N 2 O, H 2 O, H 2 O 2 , CH 4 , C 2 H 2 and C 2 H 6 ) at stand-off distances up to 50 m using realistic non cooperative targets such as wood, painted metal, and bricks. Using more widely tunable external cavity QCL, ACLaS has also been demonstrated on broadband absorbing chemicals (dichloroethane, HFC134a, ethylene glycol dinitrate and 4-nitroacetanilide solid) and on complex samples mixing narrow-band and broadband absorbers together in a realistic atmospheric background.

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Section: Current Instrumentationmentioning

confidence: 99%

High sensitivity stand-off detection and quantification of chemical mixtures using an active coherent laser spectrometer (ACLaS)

Macleod

Weidmann

2016

SPIE Proceedings

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“…As the complete description of the DIAL set-up can be found in the previous paper [5], only a concise description will be provided. The optical setup of the lidar is presented in Fig.…”

Section: Experimental Set-upmentioning

confidence: 99%

Determination of atmospheric trace gases by infrared differential absorption lidar

Vaicikauskas¹

2007

Lithuanian J. Phys.

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A differential absorption lidar system for detection of atmospheric pollutants based on the middle infrared tandem optical parametric oscillator is presented. The characteristics of the signal obtained by detecting radiation backscattered from different topographical objects were measured in the field test of the system. These characteristics were used to calculate the minimum detectable concentration of several atmospheric pollutants: ozone, methane, ammonia, etc. Most of the gases can be detected below typical background concentrations for the low-polluted atmosphere.

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“…This is because the collected energy is highly correlated with the reference photosignal. As an example, the correlation coefficient between the received photosignal and the reference photosignal of our IR lidar [11] …”

Section: Modelling Of the Lidaric Measurementsmentioning

confidence: 99%

“…The analytical model was applied to the 8-14 µm and 0.5 mJ per pulse lidar [11] operating in the topographic target mode with the 0.05 m 2 telescope and the mercury cadmium telluride detector. The fog jet plume experiment has been carried out to probe the detection of the irregular plume.…”

Section: Introductionmentioning

confidence: 99%

Application of atmosphere sensing by infrared lidars for environmental protection and industry needs

Švedas¹,

Vaicikauskas²,

Kaucikas³

2010

Lithuanian J. Phys.

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The paper analyses some equipment and methodological aspects of atmospheric pollution monitoring by infrared lidars. Features of optical parametric oscillators (including our created two-stage system) operating in the spectral ranges of molecular fundamental vibrations are discussed. The environment protection and industry demands for this remote monitoring technology are considered. Despite the progress in the technology and low detection limits achieved, the reliable and fast identification of pollutants is far from perfection. Inner and outer factors worsening the lidar performance, i. e. stability of the transmitted pulse energy, atmospheric turbulence, and irregularity of the pollutant plume near the source, are examined. A lidaric measurement model implying pulse stability was developed and applied to the 8-14 µm and 0.5 mJ per pulse lidar operating in the topographic target mode with the 0.05 m 2 telescope and the mercury cadmium telluride detector. It has been found that the laser pulse energy instability (energy dispersion parameter D) essentially worsens the detection limit in shorter ranges (<2 km for D =1%). Adaptation of lidar technology to the fast varying irregular plumes was tested experimentally. Plume detection events were processed using the probabilistic model, and the probability of false alarm was evaluated.

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Mobile spectroscopic system for trace gas detection using a tunable mid-IR laser

Cited by 13 publications

References 12 publications

High sensitivity stand-off detection and quantification of chemical mixtures using an active coherent laser spectrometer (ACLaS)

High sensitivity stand-off detection and quantification of chemical mixtures using an active coherent laser spectrometer (ACLaS)

Determination of atmospheric trace gases by infrared differential absorption lidar

Application of atmosphere sensing by infrared lidars for environmental protection and industry needs

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