Forward degenerate four-wave-mixing spectra of NO in the strong-field regime including polarization, line coupling, and multipole effects. II. Experiments

The behavior of forward degenerate four-wave-mixing spectra of NO (A) over tilde-(X) over tilde (0,0) in the presence of strong optical-fields is observed for two crossed-polarization arrangements. The NO features in terms of coupled and isolated lines are interpreted with the complete model described in the preceding paper [V. Kruger et al., paper I, Phys. Rev. 64, 012716 (2001)]. In the intermediate regime of saturation, the variation of relative line intensities with input energy is properly reproduced for NO. Thanks to these fits, we have been able to determine saturation threshold with a good accuracy. Important properties of the different polarization schemes are observed and discussed