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| Titel |
Laser-induced micro-plasmas in air for incoherent broadband cavity-enhanced absorption spectroscopy |
| VerfasserIn |
Albert Ruth, Sophie Dixneuf, Johannes Orphal |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250129604
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| Publikation (Nr.) |
 EGU/EGU2016-9741.pdf |
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| Zusammenfassung |
| Incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) is
an experimentally straightforward absorption method where the intensity of light
transmitted by an optically stable (high finesse) cavity is measured. The technique is
realized using broadband incoherent sources of radiation and therefore the amount
of light transmitted by a cavity consisting of high reflectance mirrors (typically
R > 99.9%) can be low. In order to find an alternative to having an incoherent light source
outside the cavity, an experiment was devised, where a laser-induced plasma in
ambient air was generated inside a quasi-confocal cavity by a high-power femtosecond
laser. The emission from the laser-induced plasma was utilized as pulsed broadband
light source. The time-dependent spectra of the light leaking from the cavity were
compared with those of the laser-induced plasma emission without the cavity. It was
found that the light emission was sustained by the cavity despite the initially large
optical losses caused by the laser-induced plasma in the cavity. The light sustained
by the cavity was used to measure part of the S1 ← S0 absorption spectrum of
gaseous azulene at its vapour pressure at room temperature in ambient air, as well as
the strongly forbidden γ-band in molecular oxygen (b1Σ(2,0) ← X3Σ(0,0)). |
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