Abstract

Using a high efficiency resonant cavity phase modulator at 8.4 GHz and a new low frequency demodulation technique, we have performed frequency modulation spectroscopy with a multimode laser. This system enables the sensitive detection of small absorptions by broad spectral lines as are found in atmospheric pressure broadened molecules. The technique should be especially useful for the monitoring of small concentrations of pollutants in the atmosphere. The wide continuous tunability of a multimode cw dye laser opens up applications in basic molecular spectroscopy which we are currently exploring.

© 1985 Optical Society of America