  We have studied the resonance fluorescence of a room-temperature rubidium
vapor exited to the atomic 5P3/2 state (D2 line) by powerful single-frequency
cw laser radiation (1.25 W/cm^2) in the presence of a magnetic field. In these
studies, the slow, linear scanning of the laser frequency across the hyperfine
transitions of the D2 line is combined with a fast linear scanning of the
applied magnetic field, which allows us to record frequency-dependent Hanle
resonances from all the groups of hyperfine transitions including V- and Lambda
- type systems. Rate equations were used to simulate fluorescence signals for
85Rb due to circularly polarized exciting laser radiation with different mean
frequency values and laser intensity values. The simulation show a dependance
of the fluorescence on the magnetic field. The Doppler effect was taken into
account by averaging the calculated signals over different velocity groups.
Theoretical calculations give a width of the signal peak in good agreement with
experiment.
