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| Titel |
High-resolution Fourier-transform cavity-enhanced absorption spectroscopy in the near-infrared using an incoherent broad-band light source |
| VerfasserIn |
J. Orphal, A. A. Ruth |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250019148
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| Zusammenfassung |
| An incoherent broad-band cavity-enhanced absorption (IBBCEA) set-up was used in
combination with a Fourier-transform (FT) spectrometer in order to explore the potential
of this technique for high resolution molecular spectroscopy in the near-infrared
region.[1]
Absorption spectra of overtone bands of CO2, OCS, and HD18O were measured between
5800 and 7000 cm˘1 using a small sampling volume (1100 cm3, based on a 90 cm cavity
length). The quality of the spectra in this study is comparable to that obtained with Fourier
transform spectrometers employing standard multi-pass reflection cells, which require
substantially larger sampling volumes.
High-resolution methods such as FT-IBB-CEAS also provide an elegant way to
determine effective mirror reflectivities (Reff, i.e. a measure of the inherent overall
cavity loss) by using a calibration gas with well known line strengths. For narrow
absorption features and non-congested spectra this approach does not even require a
zero-absorption measurement with the empty cavity. Absolute cross-sections or line
strengths of a target species can also be determined in one single measurement, if gas
mixtures with known partial pressures are used. This feature of FT-IBB-CEAS
reduces systematic errors significantly; it is illustrated based on CO2 as calibration
gas.
[1] J. Orphal and A. A. Ruth, "High-resolution Fourier-transform cavity-enhanced absorption
spectroscopy in the near-infrared using an incoherent broad-band light source", Optics Express 16,
19232-19243, 2008. |
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