We study the realization of an optical transistor (switch and amplifier) and router in multi-order fluorescence (FL) and spontaneous parametric four-wave mixing (SP-FWM). We estimate that the switching speed is about 15 ns. The router action results from the Autler-Townes splitting in spectral or time domain. The switch and amplifier are realized by dressing suppression and enhancement in FL and SP-FWM. The optical transistor and router can be controlled by multi-parameters (i.e., power, detuning, or polarization).

We investigated the parametrically amplified nonreciprocity of the transmission of the probe field, the reflection of suppressed four-wave mixing, the enhanced six-wave mixing and the radiation trap nonreciprocity of fluorescence signals in a five level atomic system.

The theory of proof-of-principle triple-mode squeezing is proposed via spontaneous parametric six-wave mixing process in an atomic-cavity coupled system. Special attention is focused on the role of dressed state and nonlinear gain on triple-mode squeezing process. Using the dressed state theory, we find that optical squeezing and Autler-Towns splitting of cavity mode can be realized with nonlinear gain, while the efficiency and the location of maximum squeezing point can be effectively shaped by dressed state in atomic ensemble. Our proposal can find applications in multi-channel communication and multi-channel quantum imaging.

HIGHLIGHTS• We observed Autler-Townes splitting of single peak into two and three peaks in two-level, and three-level systems, respectively. • We reported primary and secondary Autler-Townes splitting are caused by double cascaded dressing in time domain.• We observed Autler-Townes splitting of multi-order fluorescence in time domain is more obvious than that of in spectral domain.