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Proceedings Paper

Absorption spectroscopy in gases by wideband mode tunable CO2 RF laser
Author(s): S. Marchetti
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Paper Abstract

The Radiofrequency excitation of gas lasers is very attractive because it allows to operate at larger pressures with moderate transverse voltages. In this way it is possible to deposit a high energy density in short waveguides with relatively large section, to obtain an easy and large mode tuning. Efficient high pressures and high energy density discharges are possible only in a pulsed regime, because of the insufficient gas cooling. The pulsed emissions are affected by frequency chirp which acts as a mean linewidth enlargement. In spite of this effect, a mean 20-40 MHz linewidth can be always obtained. We have built two RF lasers with 506 and 920 MHz mode tuning respectively. Pulsed emission with 300-1000 PPS, 150-600 W peak power, and 0.3-3 W mean power can be obtained. By using the standard He reach laser mixtures at 1-1.5 bar we obtain the best performance, but normally we use an enexpensive He free CO2∶N2=1∶2 at 0.25-0.4 bar obtaining 65 full mode tuned lines in the longer device and 40 the the shorter one. By using both the laser we have performed a high resolution (10MHz) spectroscopy of gases which are interesting in the FIR emission, looking to a further use of our lasers in FIR laser pumping experiments

Paper Details

Date Published: 1 October 1991
PDF: 2 pages
Proc. SPIE 1576, 16th International Conference on Infrared and Millimeter Waves, 15763I (1 October 1991); doi: 10.1117/12.2297839
Show Author Affiliations
S. Marchetti, IFAM-CNR (Italy)

Published in SPIE Proceedings Vol. 1576:
16th International Conference on Infrared and Millimeter Waves
Minh Quang Tran, Editor(s)

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