title: Ramsey fringes in the nonlinear Hanle effect in a metastable atomic beam.
abstract: Evidence of coherence effects has been observed in the Zeeman sublevels by means of nonlinear level crossing in a metastable Ca beam with resonance width 3 orders of magnitude less than the radiative linewidth of the investigated transitions. By using two separate traveling waves, Ramsey-like fringes have been observed. The final measured widths are determined by the transit time, are weakly dependent on the magnetic-field inhomogeneities, and are independent of the natural width of the optical transitions and the laser bandwidth.
authors.affiliation: Dipartimento di Fisica deli' Universitá, Piazza Torricelli 2, I-56100 Pisa, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Bertuccelli
authors.forename: N
authors.initials: N
authors.lastname: Beverini
authors.forename: M
authors.initials: M
authors.lastname: Galli
authors.forename: M
authors.initials: M
authors.lastname: Inguscio
authors.forename: F
authors.initials: F
authors.lastname: Strumia