Stabilization of the waveguide CO2 laser line for a laser photoacoustic SF6-leak detector

Abstract

A compact waveguide pulse-periodic HF-excited CO2 laser with automatic tuning and wavelength stabilization at the 10P(16) generation line was designed in order to increase the accuracy of SF6 concentration measurements in air with a photoacoustic (PA) detector. The laser uses a nonselective cavity. The cavity length is tuned by a PZT actuator. A sealed-off SF6-filled PA cell is used as the reference to identify the desired laser line. The algorithm for selection and stabilization of the laser generation line is developed. The influence of different factors on the laser operation parameters is determined. The error in SF6 concentration measurements in air is less than 3% when using the designed laser. The ability of using this algorithm to stabilize other CO2 laser lines is discussed, in particular, those necessary for detecting ethylene and acetone vapors.