Autler-Townes effect in a sodium molecular-ladder scheme

Journal Article · Tue Feb 01 04:00:00 EST 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.71.023401· OSTI ID:20650097

Garcia-Fernandez, Ruth; Ekers, Aigars; Klavins, Janis; Yatsenko, Leonid P; Bezuglov, Nikolai N; Shore, Bruce W; Bergmann, Klaas ^[1]

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1. Department of Physics, University of Kaiserslautern, Erwin-Schroedinger Strasse, D-67663 Kaiserslautern (Germany)

We report results from studies of the Autler-Townes (AT) effect observed in sodium molecules from a molecular beam. A relatively weak laser field P couples an initially populated rovibronic level g in the electronic ground state (here X {sup 1}{sigma}{sub g}{sup +},v{sup ''}=0, J{sup ''}=7) to a selected excited rovibronic level e (here A {sup 1}{sigma}{sub u}{sup +},v{sup '}=10, J{sup '}=8), which in turn is coupled by a relatively strong laser field S to a more highly excited level f (here 5 {sup 1}{sigma}{sub g}{sup +},v=10, J=9), a scheme we idealize as a three-state ladder. The AT effect is seen by scanning the frequency of the P field while recording fluorescence from both the e and f levels in separate detection channels. We present qualitative theoretical considerations showing that, when the P field is weak, the ratio of doublet component areas in the excitation spectrum from level f can be used to determine the lifetime of this level. We obtain a value of 17{+-}3 ns. When the P field is stronger, such that its Rabi frequency is larger than the decay rate of level e, the fraction of f-level population that decays to the intermediate electronic state A {sup 1}{sigma}{sub u}{sup +} can be deduced from the AT spectrum. When supplemented with values of Franck-Condon and Hoenl-London factors, our measurements give a value for the branching ratio (the fraction returning to level e) of r{sub e}=0.145 with a statistical error of {+-}0.004. The use of a strong P field on the g-e transition and a weak S field as a probe on the e-f transition results in complex line shapes in the excitation spectrum of level f, not showing the familiar Autler-Townes doublet structure.

• OSTI ID: 20650097
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 71; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
BRANCHING RATIO
DECAY
DETECTION
ERRORS
EXCITATION
FLUORESCENCE
GROUND STATES
LASER RADIATION
LIFETIME
MOLECULAR BEAMS
MOLECULES
PHOTON-MOLECULE COLLISIONS
PROBES
SODIUM
STARK EFFECT
VIBRATIONAL STATES