Optical excitation of a molecular laser by a photodissociation wave propagating in a dense gas

An investigation is made of the photolysis of gaseous media accompanied by recombination reactions. It is shown that exposure of these media to high-power radiation causes complete or partial bleaching by nonsteady-state photochemical waves. High-intensity external radiation can produce high concentrations of atoms and radicals (10¹⁸–10¹⁹ cm^–3) and initiate strongly nonequilibrium recombination reactions. The conditions for a population inversion of the electronic states of molecules or recombination products are analyzed for cases when the recombination reactions have a radiative channel. An inversion may be established both under linear absorption and bleaching conditions. The results are applied to various specific mixtures for which the inversion conditions and the optical gain are calculated.