Parametric study of first-overtone CO laser with suppressed fundamental band lasing: experiment and theory

Parametric study of a first-overtone (FO) CO laser was carried out both experimentally and theoretically. A special optical filter was used for suppression of fundamental band lasing. The theoretical model is in satisfactory agreement with the experiment for a laser operating on a He-containing gas mixture. The maximum FO CO laser efficiency of 5.5% and specific output energy (SOE) of similar to 20 J/1 Amagat were obtained for a laser resonator with rather high useless optical losses, FO CO lasing taking place from 13 --> 11 up to 30 --> 28 vibrational transitions (lambda = 2.7 - 3.6 mu m). Important influence of intracavity water vapor on the output characteristics of FO CO laser and its spectrum, in particular, is discussed. Both theoretical and experimental results indicate that the FO CO laser efficiency up to 15-20% and SOE up to 50-80 J/1 Amagat can be obtained. (C) 1998 Elsevier Science B.V. All rights reserved.