title: Subnatural coherence effects in saturation spectroscopy using a single traveling wave.
abstract: We have performed zero-field level-crossing resonance measurements (nonlinear Hanle effect) in a metastable Ca atomic beam. By saturating the optical transitions (3)P(1,2) ? (3)S(1), for which the radiative linewidth is 10.5 MHz, we have recorded resonances corresponding to widths of about 31 kHz. The effect has been investigated as a function of the saturating-radiation intensity. The frequency jitter of the laser used in the measurements is about 40 times wider than the recorded widths.
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
authors.forename: G
authors.initials: G
authors.lastname: Giusfredi