Direct observation of the Autler-Townes effect in the optical range

Abstract

A two-step optical resonance experiment, which realizes the optical analogue of the Autler-Townes experiment, has been performed on a sodium atomic beam excited by two CW narrow-band dye lasers. An intense laser radiation was locked to a component of the D2 resonance line while a weak laser radiation probed an upper connected transition. A dynamic Stark splitting of the probe transition was clearly observed for various intensities of the strong resonant radiation.