Design of a difference-frequency infrared laser spectrometer for absorption line-shape studies

An infrared laser spectrometer based on difference-frequency generation in LiI[O.sub.3] is described. The spectrometer has a frequency uncertainty of less than 1 MHz and a signal-to-noise ratio between 3000:1 and 10,000:1. These properties allow the spectrometer to be used for studies of the non-Lorentzian and non-Voigt character of absorption line shapes in atmospheric trace gases. OCIS codes: 300.1030, 300.6190, 300.6320, 300.6340, 300.6360, 300.6390.