Thermal physics of transverse-discharge copper vapor lasers

One of the factors determining the ultimate characteristics of copper vapor lasers is the heating of the active medium by the pulse-periodic discharge providing the excitation. The gas temperature was measured on the axis of the discharge gap of a transversely excited copper vapor laser. Two methods were used: a spectroscopic method (based on the Doppler width of an emission line of the neon buffer gas) and an interferometric method (based on the fringe shift in a Mach–Zehnder interferometer at the instants when the discharge was switched abruptly on and off). Both methods yielded values close 2200 °K. The temperature distribution in the active zone with a rectangular cross section was computed numerically. The results of a theoretical calculation were used to estimate the efficiency of conversion of the discharge energy into heat, which was around 40%.