High homogeneity gain distribution in a cross flow AC excited CO2 laser

Gain measurements at 10.6 μm, performed on an alternating-current-excited CO₂ laser discharge, are presented. The discharge occurred between individually ballasted p-i-n electrodes. The values of the ballast capacitors were arranged in order to obtain a stable discharge as well as an almost uniform gain distribution through all of the discharge section. The results show that an appropriate distribution of the specific power density into the active medium volume can produce a stable discharge as well as good uniformity of the small-signal gain in the discharge cross section. The downstream small-signal gain, however, decreases slightly, despite a higher excitation rate, due to a higher temperature and an increased thermal population of the lower laser level. The rather high values of the small signal gain, even in the high excitation region, offer promise of good beam quality and high efficiency