Wavelength dependence of Autler-Townes splitting in a four-level ladder molecular system

¹ School of Electric Engineering, University of South China - Hengyang 421001, China
² School of Nuclear Science and Technology, University of South China - Hengyang 421001, China
³ State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics - Dalian 116023, China

^(a) luxingqiang@163.com

Received: 29 August 2014
Accepted: 26 November 2014

Abstract

We theoretically investigated the Autler-Townes (AT) splitting in the photoelectron spectra of four-level ladder K₂ molecules in the presence of two control pump fields and one probe field by employing the time-dependent wave packet approach. The wavelength dependence of AT splitting on three laser pulses was studied in detail. The photoelectron spectra show triple splitting with symmetric profiles, but with asymmetric profiles when the wavelength is changed. The shifts of the absorption peaks are predicted by using an analytical fitting function when the wavelength of one of the three fields is changed, and the functional dependence appears to be linear. These novel results are of importance for the molecular spectroscopy, and may stimulate further theoretical studies analytically from the first principles.