Resonant acoustooptic effects in a gas

Resonant two-photon scattering by acoustic vibrations of atoms or molecules in a gas is studied. It is shown that an acoustic field of frequency ω_a acting on laser radiation spectra not only gives rise to the usual spectral structures induced by a parametric resonance, but also to satellite lines at the combination frequencies ω_μ = ω ± ω_a (ω and ω_μ are the frequencies of laser fields). Possible applications of such parametric laser–acoustic resonances include the diagnostics of gaseous media and of acoustic fields.