Diode-laser absorption measurements of CO2 near 2.0 μm at elevated temperatures

A diode-laser sensor system based on absorption spectroscopy techniques has been developed for nonintrusive measurements of CO2 in high-temperature environments. Survey spectra of the CO2 (20 degrees 1,04 degrees 1)(I)-00 degrees 0 and (20 degrees 1,04 degrees 1)(II)-00 degrees 0 bands between 1.966 and 2.035 mu m (4915-5085 cm(-1)) were recorded at temperatures between 296 and 1425 K in a heated static cell and compared with calculated spectra (by using the HITRAN 96/HITEMP database) to find candidate transitions for CO2 detection. High-resolution measurements of the CO2 R(56) line shape [(20 degrees 1,04 degrees 1)(II)-00 degrees 0 band] were used to determine the transition line strength, the self-broadening half-width, and the coefficient of temperature dependence of the self-broadening half-width. The results represent what are believed to be the first measurements of CO2 absorption near 2.0 mu m with room-temperature diode lasers. Potential applications of the diode-laser sensor system include in situ combustion measurements and environmental monitoring. (C) 1998 Optical Society of America.