Abstract

With the aid of commercial room-temperature AlGaAs diode lasers, frequency modulation absorption spectroscopy was performed on the 7900 Å and 8600 Å rovibrational combination overtone bands of methane. Three weak transitions are reported in the range around 8610 Å that, to our knowledge, have not yet been observed and measured. Self-broadening and pressure-broadening coefficients of one of these new absorption features (at 8608.93 Å) were derived from CH₄ and for CH₄ immersed in N₂ and He buffer gases. An evaluation of the methane detection sensitivity is given for favorable laboratory conditions as well as for an open-path situation.

© 1993 Optical Society of America

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