FREQUENCY-MODULATION SPECTROSCOPY WITH A TUNABLE CO2 SIDE-BAND LASER - OZONE DETECTION

The unblended ozone line at 1044.533 cm(-1) was acquired by using the frequency modulation technique. A tunable CO2 sideband laser with a Ga As waveguide modulator with a tuning bandwidth of 20 GHz in the mid-in frared region was used for this method. With this technique, a second sideband at 1-MHz frequency with a peak-to-peak amplitude of 1 V was i mposed on the first tunable sideband. The signal was passed through a 1-m cell and collected with an EG&G detector. The signal-to-noise rati o obtained was approximately 100:1. (C) 1998 Optical Society of Americ a.