Abstract

It is well known that a strongly driven transition exhibits a doublet splitting when probed by a weak field, commonly known as AC Stark splitting. It can be observed either by probing the driven two-level itself (Mollow-type spectrum¹) or via a third level (Autler-Townes-type spectrum²). These two type splittings can have very different characteristics, particularly when driven resonantly. The absorptive Mellow spectrum consists of two dispersion-like features, whereas for the Autler-Townes spectrum there is a simple doublet splitting. In this paper we report the observation of both Mollow and Autler-Townes spectrum simultaneously by applying two strong driving fields in a three-level configuration (see Fig. 1), where the field ω₁ (Rabi frequency X₁) is resonant with the |1 >↔|2> transition (δ₁ = 0) and the field ω₂ (Rabi frequency X₂) drives the |1 >↔|3> transition with a detuning δ₂ = ±X₁^, and the absorptive response is recorded by scanning the |1 >↔|3> transition with a weak probe field ω₃. The detail of the three-level system and experimental method can be found elsewhere.³

© 1998 Optical Society of America