Polarization-Dressed Correlation and Anti-Correlation Between Phase-Conjugate Four-Wave Mixing and Fourth-Order Fluorescence

We report the two- and three-mode correlation of phase-conjugate four-wave mixing and fourth-order fluorescence in Pr 3+ :Y 2 SiO 5 crystal. The degree of correlation is controlled by changing the position of detecting time and polarization state of pumping field. The switching between correlation and anti-correlation was observed at different positions of detecting time because of the competition between four-wave mixing and fourth-order fluorescence signals. The obvious variation of correlation degree was also observed at different polarization states, which is interpreted by the different Clebsch–Gordan coefficients and the EIT subsystem induced by polarization dressing effect.