TUNABLE DIODE-LASER ABSORPTION-MEASUREMENTS OF NO2 NEAR 670 AND 395 NM

Two single-mode diode lasers were used to record high-resolution absor ption spectra of NO2 (dilute in Ar) near 670.2 and 394.5 nm over a ran ge of temperatures (296 to 774 K) and total pressures (2.4 x 10(-2) to 1 atm). A commercial InGaAsP laser was tuned 1.3 cm(-1) at a repetiti on rate of 1 kHz to record the absorption spectra near 670.2 nm. In se parate experiments with a prototype system, an external-cavity GaAlAs laser was frequency doubled with a quasi-phase-matched LiNbO3 waveguid e and tuned 3.5 cm(-1) to record absorption spectra near 394.5 nm. Var iations of the spectral absorption coefficients with temperature and p ressure were determined from measured spectra. (C) 1996 Optical Societ y of America