DETECTION OF POLYATOMIC-MOLECULES USING INFRARED DEGENERATE 4-WAVE-MIXING

Degenerate four-wave mixing detection of methane and acetylene is demo nstrated using rotational-vibrational transitions for resonance enhanc ement. High resolution spectra (<0.007 cm-1) of methane and acetylene, near 3000 and 3300 cm-1 respectively, have been acquired using a sing le-longitudinal-mode optical parametric oscillator. These experiments suggest that infrared degenerate four-wave mixing provides a new diagn ostic capability for the sensitive detection of polyatomic molecules w ith high temporal and spatial resolution.