Polarization dressed multi-order fluorescence of Pr³⁺:Y₂SiO₅.

We report polarization dressed second-, fourth- and sixth-order fluorescence processes in a Pr(3+):Y2SiO5 crystal. By changing the polarization states of dressing fields and generating fields, the fluorescence baselines, suppression and Autler-Townes splitting of emission peaks can be controlled. The polarization dependencies of fluorescence generated from two inequivalent crystallographic sites are compared.

Suppression and enhancement of coexisting super-fluorescence and multi-wave mixing processes in sodium vapor.

Different aspects of the properties of the coexisting super-fluorescence (SFL), multi-wave mixing with the fluorescence signal in the sodium vapor are studied both theoretically and experimentally. First, by scanning the dressed-state, the properties of these coexisting processes, such as the SFL signal modulated by using the dark and bright states, the interplay between dressed-states, are observed for the first time. Then, by scanning the probe field, the interplay between the one-photon and two-photon processes of the coexisting signals is obtained with or without the external dressing fields.

Observation of angle-modulated switch between enhancement and suppression of nonlinear optical processes.

We simultaneously investigate the four-wave mixing and the fluorescence signals via two cascade electromagnetically induced transparency (EIT) systems in atomic rubidium vapor. By manipulating the deflection angle between the probe beam and certain coupling beams, the dark state can extraordinarily switch to bright state, induced by the angle-modulation on the dressing effect. Besides, in the fluorescence signal, the peak of two-photon fluorescence due to classical emission and the dip of single-photon fluorescence due to dressing effect are distinguished, both in separate spectral curves and in the global profile of spectrum.