Tunable multiline and single-line operations on a pulsed transversely excited atmospheric pressure CO₂ laser by means of an intracavity CO₂ gas absorber

The operating rotational-vibrational transition lines are observed in a pulsed transversely excited atmospheric pressure CO₂ laser with a separated intracavity CO₂ gas absorber. The laser operates a dominant 10.6-μm P-20 and P-18 line in a low pressure of CO₂ cell and a single-line operation of P-20 line at more high pressure. In a high pressure, the laser does not operate the 10.6-μm P-20 and P-18, but it operates the single-line operation of 10.6-μm R-14, R-18, P-22, and 9.4-μm R-12, and in multiline oscillation, of various combinations of these lines and 10.6-μm R-16, according to the temperature of this gas absorber. The results are attributed to the absorbing mechanism of the CO₂ gas.