OPTICALLY ENHANCED MAGNETIC-RESONANCE FOR THE STUDY OF ATOM-SURFACE INTERACTION

We study surface-induced spin relaxation with a laser-assisted magneti c resonance experiment. Optical pumping with polarization-modulated li ght in a transverse magnetic field creates, the spin polarization. For detection a probe laser beam is reflected at the surface and the chan ge of its polarization is monitored. We present a comprehensive theore tical description, taking into account the spin relaxation at the surf ace, which leads to a spatially inhomogeneous magnetization near the s urface as a result of the transient behavior of the atoms in this regi on. Analytical expressions are derived for the magnetic resonance sign al, which show that the wall relaxation causes a clear modification of the line shape, characterized by pronounced wings. The experimental r esults obtained with bare and silicone-coated Pyrex-glass surfaces are well described by the theory. The bare glass surface causes strong re laxation, whereas the silicone-coated surface is only weakly depolariz ing. The analysis of the magnetic-resonance line shape indicates that the depolarization probability per wall collision is similar to 0.01 i n the latter case. The results:are compared with corresponding results from the analysis of the optical resonance line measured with the sam e setup. Both types of measurements can be interpreted within the same theoretical framework and are fully consistent with one another.