Optically enhanced magnetic resonance for the study of atom-surface interaction

Abstract. We study surface-induced spin relaxation with a laser-assisted magnetic resonance experiment. Optical pumping with polarization-modulated light in a trans-verse magnetic field creates the spin polarization. For detection a probe laser beam is reflected at the surface and the change of its polarization is monitored. We present a comprehensive theoretical description, taking into account the spin relaxation at the surface, which leads to a spatially inhomogeneous magnetization near the sur-face as a result of the transient behavior of the atoms in this region. Analytical expressions are derived for the magnetic resonance signal, which show that the wall relaxation causes a clear modification of the line shape, characterized by pronounced wings. The experimental results obtained with bare and silicone-coated Pyrex-glass surfaces are well described by the theory. The bare glass surface causes strong relaxation, whereas the silicone-coated surface is only weakly depolarizing. The analysis of the magnetic-resonance line shape indicates that the de-polarization probability per wall collision is &0.01 in the latter case. The results are compared with corresponding results from the analysis of the optical resonance line measured with the same setup. Both types of measure-ments can be interpreted within the same theoretical framework and are fully consistent with one another. PACS: 34.50.Dy; 32.30.Dx; 32.70.Jz I