Abstract

A novel, compact, ultrasensitive, and inexpensive He-Ne laser intracavity photothermal deflection spectrometer has been developed. In this apparatus a gas sample is placed inside a cavity of the He-Ne laser, which serves as a probe laser. A CO₂ excitation laser coaxially overlaps with the He-Ne laser beam inside the sample cell. The detection limit for ethanol vapor in air at 1 atm excited with 1.5 W of CO₂ laser chopped at 13.3 Hz is estimated to be 2.5 ppb.

Trace gas detection by laser intracavity photothermal spectroscopy

K. H. Fung and H.-B. Lin
Appl. Opt. 25(5) 749-752 (1986)

Applications of a compact photothermal-deflection-based setup for trace-gas detection in real-time in situ environmental monitoring and chemical analysis

Bob L. Zimering and A. Claude Boccara
Appl. Opt. 36(15) 3188-3194 (1997)

Sensitive photothermal deflection technique for measuring absorption in optically thin media

A. C. Boccara, D. Fournier, Warren Jackson, and Nabil M. Amer
Opt. Lett. 5(9) 377-379 (1980)

Quantitative photothermal deflection spectroscopy in a flowing stream of gas

Jeffrey A. Sell
Appl. Opt. 23(10) 1586-1597 (1984)

Multicomponent trace-gas analysis by three intracavity photoacoustic cells in a CO laser: observation of anaerobic and postanaerobic emission of acetaldehyde and ethanol in cherry tomatoes

Frans G. C. Bijnen, Hanna Zuckermann, Frans J. M. Harren, and Jörg Reuss
Appl. Opt. 37(15) 3345-3353 (1998)