Abstract

Recently, a frequency modulated Ti:sapphire laser was used as a highly sensitive means for detection of transient species (1). In particular it was used to measure spectra of methylene and its halo-derivatives (2,3) and in addition very high signal-to-noise Doppler lineshapes were recorded from which significant dynamical analyses have derived (4). Within the last year we have incorporated the frequency modulation (FM) method into a near-infrared diode laser system which works at wavelengths around 1 μm and this has produced an order of magnitude improvment in signal-to-noise of that system. A further improvement in sensitivity has been achieved by extending the interaction region of the probing laser and the gas sample using a Herriott-type cell. Systems based upon this diode laser spectrometer which is cheap, simple to use and maintain, and relatively compact may provide a sensitive monitor of important gaseous molecules that absorb at similar wavelengths.

© 1998 Optical Society of America