Near- and mid-infrared laser monitoring of industrial processes, environment and security applications

Willer, Ulrike; Saraji, Mohammad; Khorsandi, Alireza; Geiser, Péter; Schade, Wolfgang

doi:10.1016/j.optlaseng.2005.04.015

Cited by 287 publications

(137 citation statements)

References 19 publications

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“…Willer et al, showed how difference frequency generation using two narrow band tunable diode lasers can generate narrow band tunable mid infrared, and demonstrated detection of NO vapor from laser ablation of different trace amounts of explosives on surfaces [99]. They propose to distinguish between explosives via the time dependent NO production rate with ablation laser pulse energy, repetition rate, and wavelength.…”

Section: Infrared Absorption Spectroscopymentioning

confidence: 99%

Recent Advances in Trace Explosives Detection Instrumentation

2007

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There has been a huge increase in instrument development for trace detection of explosives in the past 3 years. This is especially true for methods that can be used at a stand off distance, driven by the frightening increase in the use of improvised explosive devices in both suicide and road side bombings. This review attempts to outline and enumerate these recent developments, with details about the improvements made as well as where further improvements might come.

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Section: Infrared Absorption Spectroscopymentioning

confidence: 99%

Recent Advances in Trace Explosives Detection Instrumentation

2007

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“…Although H 2 S the infrared (IR) spectral region. Sensors based on tuneable diode laser absorption spectroscopy (TDLAS) mostly utilize near-infrared diode lasers due to their distinguished properties, such as single-mode operation, good beam quality, high repetition rate, relatively narrow line width, large current tuning range, good operability, low power consumption and low investment costs [9][10][11]. When measuring H 2 S by IR spectroscopy, high sensitivities are difficult to achieve.…”

Section: Introductionmentioning

confidence: 99%

Cantilever-enhanced photoacoustic detection of hydrogen sulfide (H2S) using NIR telecom laser sources near 1.6 µm

Moser

Lendl

2016

Appl. Phys. B

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concentrations as low as 500 pptv manifesting in the characteristic odor of rotten eggs can already be detected by the human olfactory sense, the total loss of olfactory sensation starts at 150-200 ppmv [3]. Because of the wide occurrence of H 2 S in industrial processes and its often negative impact on process stabilities and product quality, its concentration needs to be tightly monitored. Furthermore, safety considerations and legal concentration limits also necessitate the accurate determination of H 2 S levels. In practice, concentrations ranging from sub-ppm levels at low pressures to several per cents at atmospheric conditions need to be monitored. Due to such diverse requirements, H 2 S analyzers based on different measurement technologies have been developed and are in industrial use. Apart from spectroscopic techniques based on absorption measurements, a range of other analytical techniques such as pulsed UV fluorescence [4], sulfur chemiluminescence [5], colorimetry employing a lead acetate tape [6], flame photometry as detector in gas chromatography [7] as well as electrochemical detection techniques ranging from potentiometric, galvanic, coulometric and amperometric detection [8] is frequently employed. It is interesting to note that in the petrochemical industry the lead acetate tape method is still in frequent use. Also, gas chromatographic methods are popular as they can be used to detect several components almost simultaneously, but this technique requires preparation and extraction of the sample gas leading to a time-consuming measurement. A general drawback of nonspectroscopic techniques is the fact that they do not allow for direct measurements. This, however, also applies to H 2 S detection based on UV fluorescence as this technique requires sample combustion as well as detection by chemoluminescence, where addition of reagents is required.Most of the spectroscopic techniques are based on the detection of the absorption spectrum of the molecules in Abstract Sensitive detection of hydrogen sulfide (H 2 S) at different pressure levels using a cantilever-enhanced photoacoustic detector in combination with a telecom NIR L-band laser source is reported. Amplitude and wavelength modulation schemes for photoacoustic signal generation are compared. A detection limit (3σ) of 8 ppmv was achieved for amplitude modulation mode with a 50-s averaging time for the H 2 S absorption near 1.6 µm. As compared to simulated spectra, the cantilever-enhanced photoacoustic detection approach in combination with the sufficiently stable and narrow bandwidth NIR laser is able to reproduce the rotationally resolved H 2 S spectrum at low pressures of 300 mbar.

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“…Laboratory procedures routinely in place for the identification of illicit forensic samples include, but are not limited to, colour tests, microcrystal tests, high performance liquid chromatography mass spectroscopy, [1,2] ultra violet spectrophotometry, [3,4] gas chromatography mass spectroscopy, [5] Fourier transform infrared (FTIR) spectroscopy, [6] X-ray powder diffraction and ion mobility spectrometry. [7] In the last decade, Raman spectroscopy has emerged with huge potential for the forensic examination of materials.…”

Section: Introductionmentioning

confidence: 99%

Comparison of near infrared laser excitation wavelengths and its influence on the interrogation of seized drugs‐of‐abuse by Raman spectroscopy

Hargreaves

Burnett

Munshi

et al. 2009

J Raman Spectroscopy

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aThe laser excitation wavelength is an important parameter in obtaining Raman spectra from drugs-of-abuse. This article compares the effect of near infrared wavelengths, 785 nm, using both benchtop and portable instrumentation and benchtop 1064 nm on the Raman spectra of seized drugs-of-abuse, including cocaine hydrochloride, cocaine freebase (crack), methylenedioxymethamphetamine ('ecstasy'), amphetamine, diamorphine (heroin) and cannabis. The significant benefit of using 1064 nm for the interrogation of this type of sample is highlighted.

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Near- and mid-infrared laser monitoring of industrial processes, environment and security applications

Cited by 287 publications

References 19 publications

Recent Advances in Trace Explosives Detection Instrumentation

Recent Advances in Trace Explosives Detection Instrumentation

Cantilever-enhanced photoacoustic detection of hydrogen sulfide (H2S) using NIR telecom laser sources near 1.6 µm

Comparison of near infrared laser excitation wavelengths and its influence on the interrogation of seized drugs‐of‐abuse by Raman spectroscopy

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