Gas Temperature Analysis of Laser Gain Medium in a Slab-type Radio-frequency-discharge-excited CO2 Laser

An optical method of temperature measurement to analyze CO2 laser active medium based on near-infrared absorption spectroscopy with a 1.6-µm distributed-feedback (DFB) semi- conductor laser is described in this paper. The method was used to measure gas temperatures in the range 400 K to 530 K for discharge electrode distances of 5 and 7.5 mm. Real-time temperature monitoring of CO2 was achieved by using the DFB semiconductor laser. Such near-infrared absorption spectroscopy has the potential to be a practical method for diagnostic of the active medium of a CO2 laser.