A small size tunable diode laser (TDL) spectrometer with dimensions of only 280 x 190 x 130 mm (11 x 7.5 x 5 inch) was built for automated field use. The water-protected package also contains batteries and a data storage device for an independent operation of 15 hours. Mass of the complete instrument is 5 kg. Smallest absorptions recorded in fully auto-mated operation are in the 10^-5 range. Data is stored as direct absorptions and as derivative as well. The instrument can be equipped with near infrared (NIR) laser diodes depending on target species (e.g. water vapor or methane). A high dyna-mic range is achieved by periodically tuning the laser over various molecular absorption lines of different line strength using temperature scan. The absorption path is set up using a retroreflector, the pathlength can be between 0.5 meters and 100 meters depending on requirements. The instrument is targeted at reliable and sensitive field measurements in fully automated and unattended mode, including e.g. aircraft and environmental measurements.

Date Published: 23 September 2002
PDF: 6 pages
Proc. SPIE 4817, Diode Lasers and Applications in Atmospheric Sensing, (23 September 2002); doi: 10.1117/12.447887

Published in SPIE Proceedings Vol. 4817:
Diode Lasers and Applications in Atmospheric Sensing
Alan Fried, Editor(s)