Optical quenching of metastable magnesium

Journal Article · Mon Oct 15 04:00:00 EDT 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.76.043406· OSTI ID:21020749

Rehbein, Nils; Mehlstaeubler, Tanja E; Keupp, Jochen; Moldenhauer, Karsten; Rasel, Ernst M; Ertmer, Wolfgang; Douillet, Albane; Michels, Volker; Porsev, Sergey G; Derevianko, Andrei; Froese Fischer, Charlotte; Tachiev, Georgio I; Pal'chikov, Vitaly G ^[1]

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1. Institut fuer Quantenoptik, Leibniz Universitaet Hannover, Welfengarten 1, 30167 Hannover (Germany)

Doppler cooling on narrow transitions has become a crucial technique for preparing ultracold samples of alkaline-earth-metal and alkaline-earth-metal-like atoms. For lighter species, such as calcium and magnesium, this technique relies on artificial broadening (quenching) of the upper level of the narrow line. We report on quenching experiments on a {sup 24}Mg atomic beam. The branching ratio of the (3s4s){sup 1}S{sub 0} state was determined to be {beta}=(1.33{+-}0.53)x10{sup -5} from the measured quenching efficiency. The branching ratio combined with the known linewidth of this state yields a transition rate for (3s3p){sup 3}P{sub 1}{yields}(3s4s){sup 1}S{sub 0} of {gamma}{sub 23}=283{+-}114 s{sup -1}, i.e., one order of magnitude smaller than estimated from semiempirical data. We have applied different numerical approaches, including ab initio relativistic many-body calculations, to compute the transition probabilities of the (3s3p){sup 3}P{sub 1}{yields}(3s4s){sup 1}S{sub 0} and (3s3p){sup 1}P{sub 1}{yields}(3s4s){sup 1}S{sub 0} transitions. The results are in good agreement with our experimental observation. With the measured branching ratio, we expect a transfer efficiency of Doppler-cooled atoms into a quench magneto-optical trap (QuenchMOT) of approximately 1% for our experimental parameters. According to our simulations, the transfer efficiency can be increased by one order of magnitude for lower ensemble temperatures as recently demonstrated by two-photon cooling in our uv MOT.

• OSTI ID: 21020749
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 76; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ALKALINE EARTH METALS
ATOMIC BEAMS
ATOMS
BRANCHING RATIO
CALCIUM
DOPPLER BROADENING
ELECTRONIC STRUCTURE
ENERGY-LEVEL TRANSITIONS
LASER RADIATION
LIFETIME
MAGNESIUM
MAGNESIUM 24
MANY-BODY PROBLEM
METASTABLE STATES
PHOTONS
QUENCHING
RELATIVISTIC RANGE
SIMULATION
TEMPERATURE RANGE 0000-0013 K