The polarization properties of backward-box, degenerate four-wave mixing from OH molecules are measured in a flame and compared with theory. Ratios of signal intensities for different laser polarizations are shown to exceed perturbation-theory predictions for a closed two-level system when optical intensity gratings are formed in the interaction volume. These results are shown to be inconsistent with population-nonconserving effects and are attributed to scattering from quenching-induced thermal density gratings.
© 1994 Optical Society of America
Larry A. Rahn and Michael S. Brown, "Polarization properties of degenerate four-wave mixing in flame OH," Opt. Lett. 19, 1249-1251 (1994)