MAGNETIC INHIBITION OF POLARIZATION-GRADIENT LASER COOLING IN SIGMA(-SIGMA(-)-OPTICAL MOLASSES())

Xenon atoms are released from a magneto-optical trap and equilibrate i n a one-dimensional, sigma(+)-sigma(-) optical molasses, along which a uniform magnetic field is applied. In the rest frame of the ''corkscr ew'' pattern of laser polarization, the magnetic field induces a nonze ro average atomic velocity. Introducing a moving molasses through a re lative difference in the two laser-beam frequencies allows straightfor ward, accurate measurements of the molasses-frame velocity distributio n over a large range of magnetic fields. The measurements reveal the l oss of polarization-gradient cooling in fields higher than similar to 0.2 mT, in quantitative agreement with theoretical predictions.