Narrow magnetooptic absorption resonances in a gas due to the nonlinear Faraday effect

A study of resonant interaction of He–Ne laser radiation with the 3s₂–2p₄ neon transition (of 0.63 μ wavelength) and with the vibrational-rotational F₂⁽²⁾methane transition P(7) line of the ν₃ band at 3.39 μ] revealed narrow magnetooptic resonances due to the nonlinear Faraday effect. An analysis was made of the dependences of magnetooptic spectral structures of this type on the angular momenta of the energy levels and on disorienting collisions in the gas. It was established that the method of recording the nonlinear magnetooptic resonances resulting from the Faraday rotation had a higher sensitivity than the normal method of measuring magnetooptic absorption resonances.