Intensity dependence suppression and enhancement of four-wave mixing in a micrometric thin vapour

Abstract

We theoretically investigate dressed-four-wave mixing (dressed-FWM) spectroscopy of rubidium atoms in a micrometric thin vapour. It is found that Dike-narrowing type Autler–Townes (AT) spectroscopy with high resolution can be achieved in a reverse Y-type four-level atomic system due to the phase-conjugated configuration of laser beams and the transient effects of atom–wall collision in the thin vapour. We also show that controllable suppression and enhancement of the dressed-FWM signal due to the evolution of atomic coherence can be obtained by selecting different coupling field intensities at the proper detuning of the probe and the coupling fields. This control of FWM processes can be interpreted by dressed state analysis and probably used in the design of optical switch and the enhancement of FWM processes for frequency conversion.