Prospects for measurement and control of the scattering length of metastable helium using photoassociation techniques
École Normale Supérieure and Collège de France,
Laboratoire Kastler Brossel, 24 rue Lhomond, 75231 Paris Cedex 05,
Corresponding author: a email@example.com
Published online: 23 November 2004
A numerical investigation of two-laser photoassociation (PA) spectroscopy on spin-polarized metastable helium (He*) atoms is presented within the context of experimental observation of the least-bound energy level in the scattering potential and subsequent determination of the s-wave scattering length. Starting out from the model developed by Bohn and Julienne [Phys. Rev. A 60, 414 (1999)], PA rate coefficients are obtained as a function of the parameters of the two lasers. The rate coefficients are used to simulate one- and two-laser PA spectra. The results demonstrate the feasibility of a spectroscopic determination of the binding energy of the least-bound level. The simulated spectra may be used as a guideline when designing such an experiment, whereas the model may also be employed for fitting experimentally obtained PA spectra. In addition, the prospects for substantial modification of the He* scattering length by means of optical Feshbach resonances are considered. Several experimental issues relating to the numerical investigation presented here are discussed.
PACS: 34.20.Cf – Interatomic potentials and forces / 32.80.Pj – Optical cooling of atoms; trapping / 34.50.Gb – Electronic excitation and ionization of molecules; intermediate molecular states (including lifetimes, state mixing, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004