Spectroscopic trace gas analysis using semiconductor diode lasers

Year: 1996

Authors: Werle P.

Autors Affiliation: Fraunhofer Inst. Atmospharische U., Kreuzeckbahnstr. 19, D-82467 Garmisch-Partenkirchen, Germany

Abstract: Sensitivity, specificity, high time resolution, cost effective simultaneous measurements of several species and operational systems are the main requirements for in situ trace gas analysis in atmospheric research and process monitoring applications. Tunable diode laser absorption spectroscopy is increasingly being used to measure atmospheric trace gas concentrations down to low ppb-levels and the technique fulfills the requirements for trace gas analysis in the atmosphere for most of the smaller molecules with resolved absorption spectra. Semiconductor lead-salt diode-lasers give access to the mid infrared spectral region, where the most important atmospheric constituents have strong rotational vibrational absorption bands. The application of high frequency modulation (FM) schemes further improves sensitivity and detection speed of modern instrumentation. In this paper the FM technique will be reviewed with emphasis to the work, which has been done in our laboratory and findings from recent investigations, as well as novel approaches will be discussed. Some applications related to quality control and ISO calibration in addition to measurement challenges for fast and high sensitivity applications will be addressed.

Journal/Review: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

Volume: 52 (8 PART 3)      Pages from: 805  to: 822

More Information: This work was funded by the German Ministerium fiir Forschung und Technologie (BMFT) under grant 08431095, 07EU702 and 07EU712 as a contribution to the EUROTRAC subproject JETDLAG and by the Bayerisches Staatsminis-terium ffir Wirtschaft und Verkehr (3625-VIII/4c).
KeyWords: Diode laser; High resolution spectroscopy; Trace gas analysis
DOI: 10.1016/0584-8539(95)01607-4