Degenerate multiphoton parametric scattering of infrared radiation by vibrational–rotational molecular transitions

Resonance multiphoton parametric forward scattering of CO₂ laser radiation was observed in gaseous SF₆. Studies were made of different self-diffraction orders, up to the third inclusive. The small-signal gain due to stimulated parametric processes was 8. The experiments were used to estimate the effective nonlinear susceptibilities (nonlinear interaction coefficients) of the third, fifth, and seventh orders. The investigated effect could have a significant influence on the nonlinear optical processes, including wavefront reversal.