Intracavity laser absorption spectroscopy using mid-IR quantum cascade laser

Medhi, Gautam; Muravjov, A. V.; Saxena, H.; Fredricksen, Christopher J.; Brusentsova, T. N.; Peale, Robert E.; Edwards, Oliver

doi:10.1117/12.883331

Cited by 9 publications

(9 citation statements)

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“…Light absorption, mainly as an extinction‐based technique, is frequently used for the detection of soot aerosols 45. Intracavity absorption of laser light by aerosol particles leads to a dramatic reduction of the emitted laser light, and could be used in principle for the in situ extinction measurement 46. Only one application on re‐dispersed graphene oxide aerosol has been reported to date.…”

Section: Soot Characterization By Interaction With Electromagneticmentioning

confidence: 99%

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The Many Faces of Soot: Characterization of Soot Nanoparticles Produced by Engines

Niessner

2014

Angew Chem Int Ed

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Soot nanoparticles produced by engines constitute a threat to human health. For the analytical chemist, soot is a hard nut to crack as the released particles undergo rapid changes in their size, shape, and number concentration. The complete characterization of soot will be essential to meet future low-emission standards. Besides measuring the light extinction, modern analytical chemistry can determine a variety of less-known effects, such as condensation properties, immune response in vertebrates, and impact on the cardiovascular function of a beating heart. Photon emission and in particular Raman spectroscopy provides information on the nanocrystallinity, while thermoelectron emission allows the number of electrical particles to be counted. Even the "simple" combustion of soot nanoparticles offers potential for the characterization of the particles.

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Section: Soot Characterization By Interaction With Electromagneticmentioning

confidence: 99%

“…in situ measurement of light extinction; dependent on particle size, shape, and refractive index46–48…”

Section: Introductionmentioning

confidence: 99%

The Many Faces of Soot: Characterization of Soot Nanoparticles Produced by Engines

Niessner

2014

Angew Chem Int Ed

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“…Daher wird die Lichtabsorption, überwiegend als extinktionsbasierte Technik, häufig für die Aerosoldetektion angewendet 45. Die Intrakavitäts‐Laserlicht‐Absorption durch Aerosolpartikel führt beispielsweise zu einer drastischen Reduktion des vom entsprechendem Laser emittierten Lichts und kann daher prinzipiell für die In‐situ‐Extinktionsmessung von Aerosolen angewendet werden 46. Bis heute ist eine solche Anwendung jedoch nur für redispergiertes Graphenoxid‐Aerosol bekannt.…”

Section: Ruß‐charakterisierung Mittels Wechselwirkung Mit Elektromunclassified

Die vielen Gesichter von Ruß: Charakterisierung verbrennungsmotorischer Ruß‐Nanopartikel

Niessner

2014

Angewandte Chemie

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Ruß‐Nanopartikel (NP) aus verbrennungsmotorischen Prozessen stellen eine Bedrohung für die menschliche Gesundheit dar. Für den analytischen Chemiker ist Ruß eine harte Nuss, denn die emittierten Ruß‐Partikel unterliegen raschen Veränderungen bezüglich ihrer Größe, Form und Anzahlkonzentration. Um die immer strenger werdenden Emissionsgrenzwerte einhalten zu können, ist eine umfassende Charakterisierung des emittierten Rußes notwendig. Neben der Messung der Lichtextinktion verwendet man zu diesem Zweck auch eine Reihe weniger bekannter Effekte wie das Kondensationsverhalten von flüchtigen Substanzen auf der Partikeloberfläche, Immunantworten von Wirbeltieren auf Exposition gegenüber diesen Partikeln oder den Einfluss der Nanopartikel auf die kardiovaskuläre Funktion eines schlagenden Herzens. Des Weiteren lassen die Lichtemission und insbesondere die Raman‐Spektroskopie Rückschlüsse über die Nanokristallinität der Ruß‐Partikel zu. Die Emission von thermischen Elektronen ermöglicht außerdem die elektrische Partikelzählung im Aerosol. Sogar die Verbrennung der Ruß‐NP birgt Potential für die Charakterisierung dieser Partikel.

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“…11 The mid-IR molecular fingerprint region has remained largely unexplored by this technique until recently. [12][13][14][15][16][17] A mid-IR ICLAS system would have broad application in defense, security, environmental monitoring, medical diagnostics, etc.…”

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confidence: 99%

“…The use of the parabolic mirror and the absence of intracavity windows avoid unwanted reflections by dielectric interfaces, which cause an undesirably sparse spectrum. 14 The strong temperature dependence of the QCL spectrum requires strict thermal stabilization to achieve the highest sensitivity. The QCL temperature rises rapidly during the first 1 ms of excitation and stabilizes after about 10 ms, as indicated by the time-dependent mode spectrum.…”

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confidence: 99%

Quantum cascade laser intracavity absorption spectrometer for trace gas sensing

Muraviev¹,

Maukonen²,

Fredricksen³

et al. 2013

Applied Physics Letters

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A mid-infrared intracavity laser absorption spectrometer for trace gas sensing is demonstrated. An external-cavity multi-mode quantum cascade laser with central wavelength 8.0 μm was combined with a scanning Fabry-Perot interferometer, which analyzed the change of the laser emission spectrum caused by introducing an analyte inside the cavity. The detection mechanism is based on monitoring the laser spectrum dynamics at adiabatically changing laser conditions in long pulse operation mode. Fast acquisition and vapor exchange allow nearly real-time analyte detection. Sensitivity at the level of 1 × 10−5 cm−1 was demonstrated based on a weak water vapor absorption line.

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Intracavity laser absorption spectroscopy using mid-IR quantum cascade laser

Cited by 9 publications

References 0 publications

The Many Faces of Soot: Characterization of Soot Nanoparticles Produced by Engines

The Many Faces of Soot: Characterization of Soot Nanoparticles Produced by Engines

Die vielen Gesichter von Ruß: Charakterisierung verbrennungsmotorischer Ruß‐Nanopartikel

Quantum cascade laser intracavity absorption spectrometer for trace gas sensing

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