The absorption properties of degenerate two-level atomic systems rested by
a weak probe field in the presence of an intense pump field have been analy
zed. The theoretical model previously resented in Phys. Rev. A 61, 013801 (
1999) that appears to be suitable for arbitrary choices of the pump intensi
ty, level angular momenta, and pump and probe polarizations, was used for t
he calculation of the spectra for several basic configurations. Experimenta
l absorption spectra obtained on a Rb atomic beam for different pump and pr
obe field polarizations show good agreement with the calculation. The spect
ra are in general essentially different from and more complex than the clas
sical Mollow absorption triplet.