Polarization controlled hybrid line shape and switching of noise correlation via Autler-Town splitting

We report the experimental observations of the second- and third-order hybrid intensity noise correlation and intensity difference squeezing among two different multi-order nonlinear fluorescence (FL) and two FL signals as well as one of pair of phase conjugate four-wave mixing in a Pr³⁺:Y₂SiO₅ crystal, respectively. The degrees of the correlation and squeezing as well as the sharp and broad peaks are studied by changing the polarization of laser fields and gate position in Λ-type three-level systems. We observed the multi-channel hybrid intensities' correlation among the composite and coexisting signals, which turn out to be positive and negative for the cases without and with Autler-Town splitting of FL, respectively. A wide broad peak and a high sharp peak are observed with respect to the degrees of correlation and polarization state controlled by wave plates. Such results may find potential applications in optical transistor and optical hybrid communications.