Efficient pulsed first-over-tone CO laser operating within the spectral range of 2.5-4.2 mu m

Output characteristics of a single-pulse e-beam controlled discharge laser operating on the first-overtone (FO) transitions (Delta v = 2) of CO molecu les have been studied both experimentally and theoretically. Various sets o f dielectric mirrors with high reflectivity in the range of the overtone sp ectrum have been used for the laser resonator. Multiwavelength lasing has b een obtained in the wide spectral range of 2.5-4.1 mu m on vibrational tran sitions from 6 --> 4 up to 37 --> 35. A maximum output efficiency of 11%, t he highest ever published for a FO CO laser, has been experimentally obtain ed for the broad-band multiline FO CO laser. Maximum specific output energy is 50 J/l Amagat, FO CO lasing was observed within a predischarge gas temp erature range of 100-220 K, Spectral characteristics of the overtone laser operating on a selected set of vibrational bands have been analyzed theoret ically. Theoretical calculations based on the experimental data predict tha t multiline FO CO laser efficiency can be increased up to 20%, Experiments with a single-pulse FO CO laser using a diffraction grating as a frequency- selective element demonstrated the feasibility of developing a frequency-tu nable single-line FO CO laser. Tunable FO CO lasing on wavelengths from 2.7 up to 4.2 mu m corresponding to vibrational transitions from 13 --> 11 up to 38 --> 36 was obtained. The maximum specific output energy came up to 2. 8 J/l Amagat, with single-line output efficiency being up to 0.6%.