Formation of amplitude gratings in the medium of a CO laser subject to the field of its own multifrequency radiation

It is shown that, under conditions typical of the active medium of a continuous-flow CO laser, large-scale gain gratings play the main role in a phase-conjugation system based on degenerate four-wave mixing. The multifrequency nature of the emission spectrum of a CO laser increases the depth of modulation of the amplitude gratings as a result of two principal mechanisms: the dependence of the rate of relaxation of the function describing the distribution of molecules between vibrational levels on the number of such levels, when this function is disturbed; and the mutual influence of the emission and amplification processes involving adjacent vibrational transitions.