The Autler-Townes doublet in a pulse-driven quantum emitter.

Antônio Augusto Soares, Luı́s E. E. de Araujo

We study theoretically the interaction between an ultrashort pulse train and a three-level atom driven by a cw laser. We show that the pulse train can be employed to observe spectra of Autler–Townes doublet and electromagnetically induced transparency resonance that are time and frequency resolved. The observation of subnatural linewidth features associated with the electromagnetically induced transparency resonance is described. The temporal evolution of electromagnetically induced transparency of the pulse train is shown to exhibit new and different features compared to that of the related phenomenon of coherent population trapping. By matching the tooth separation of the frequency comb associated with the pulse train to that of the Autler–Townes doublet, quantum beats between the doublet components can be induced. We show that coherent accumulation of excitation plays a major role in the two studied phenomena.

Herbert F. Fotso, V. V. Dobrovitski

Glenn S. Solomon, Charles Santori, Axel Kuhn

Tim Bayer, Kevin Eickhoff, D. Köhnke +1 more

We propose a scheme to control the shape of the Autler-Townes (AT) doublet in the photoelectron spectrum from atomic resonance-enhanced multiphoton ionization (REMPI). The scheme is based on the interference of two AT doublets created by ionization of the strongly driven atom from the ground and the resonantly excited state using tailored bichromatic femtosecond laser pulses. In this scheme, the quantum phase of the photoelectrons is crucial for the manipulation of the AT doublet. The laser polarization state and the relative optical phase between the two colors are used to manipulate the interference pattern. We develop an analytical model to describe the bichromatic REMPI process and provide a physical picture of the control mechanism. To validate the model, the results are compared to an ab initio calculation based on the solution of the two-dimensional time-dependent Schr\"odinger equation for the nonperturbative interaction of an atom with intense polarization-shaped bichromatic femtosecond-laser pulses. Our results indicate that the control mechanism is robust with respect to the laser intensity, facilitating its experimental observation.

Lijun Yang, Min Zhao, Lianshui Zhang +1 more

The effect of the Bloch-Siegert shift on a strongly driven transition is further investigated in a V-shaped three-level configuration. Under the condition of taking into account the counter-rotating component, the absorption profiles of the probe field is dominated by a series of doublets, including well-known Autler-Townes doublet and its high-order resonances. The dependence of properties of the secondary Autler-Townes doublet on the driving Rabi intensity is discussed in this paper.

Adrian Alscher, Hermann Grabert