Experimental control of excitation flow produced by delayed pulses in a ladder of molecular levels

Ruth Garcia-Fernandez*, Bruce W. Shore, Klaas Bergmann, Aigars Ekers, Leonid P. Yatsenko

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We study a method for controlling the flow of excitation through decaying levels in a three-level ladder excitation scheme in Na2 molecules. Like the stimulated Raman adiabatic passage (STIRAP), this method is based on the control of the evolution of adiabatic states by a suitable delayed interaction of the molecules with two radiation fields. However, unlike STIRAP, which transfers a population between two stable levels g and f via a decaying intermediate level e through the interaction of partially overlapping pulses (usually in a Λ linkage), here the final level f is not long lived. Therefore, the population reaching level f decays to other levels during the transfer process. Thus, rather than controlling the transfer into level f, we control the flow of the population through this level. In the present implementation a laser P couples a degenerate rovibrational level in the ground electronic state X 1Σg+, v″=0, j″=7 to the intermediate level A 1Σu +, v′ = 10, J′ = 8, which in turn is linked to the final level 5 1Σg+, v = 10, J = 9 by a laser S, from which decay occurs to vibrational levels in the electronic A and X states. As in STIRAP, the maximum excitation flow through level f is observed when the P laser precedes the S laser. We study the influence of the laser parameters and discuss the consequences of the detection geometry on the measured signals. In addition to verifying the control of the flow of population through level f we present a procedure for the quantitative determination of the fraction κf of molecules initially in the ground level which is driven through the final level f. This calibration method is applicable for any stepwise excitation.

Original languageEnglish (US)
Article number014301
JournalJournal of Chemical Physics
Issue number1
StatePublished - 2006
Externally publishedYes

Bibliographical note

Funding Information:
One of the authors (R.G.F.) acknowledges support by the EU through the research training network QUACS (HPRN-CT-2002-0309). Another author (L.P.Y.) acknowledges support by the Deutsche Forschungsgemeinschaft through (436-UKR-113/6). Two authors (B.W.S. and L.P.Y.) acknowledge support through funds from the Max-Planck Forschungspreis 2003. Another author (A.E.) acknowledges the support by the EU TOK project LAMOL (MTKD-CT-2004-014228), European Social Fund, Latvian Science Council, and NATO Grant No. EAP.RIG.981387. The authors thank Olivier Dulieu for providing his theoretical results about radiative decay properties prior to publication.

ASJC Scopus subject areas

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


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