Temperature measurement of CO₂ by use of a distributed-feedback diode laser sensor near 2.0 μm

Temperature measurement is realized by scanning two absorption lines of CO₂ using distributed-feedback diode laser near 2.0 μm. The fundamental of temperature measurement by tunable diode laser absorption spectroscopy (TDLAS) is introduced, and multi-line nonlinear fitting method is proposed. The experiment is carried out in a heated static quartz cell at normal pressure. Within the temperature range from 900 K to 1200 K, the difference between TDLAS and S-thermocouple is less than 8%. Relative error between measured line-strength at 5007.7874 cm^-1 and the theoretical value is less than 14%. The result analysis can be useful for the further research on concentration and temperature measurement by a single diode laser.