A method for controlling the spins of atoms using optical near-fields

On the basis of the procedure for controlling the spins of atoms using circularly polarized evanescent light proposed by Hori et al.[(1996) Abstracts of the 1st Asia-Pacific Workshop on Near-field Optics] we discuss the influence of boundary conditions on the probability of spontaneous emission and thus on the spin polarization efficiency, which was not considered in the Hori et al. study. Using the Carniglia-Mandel mode expansion of electromagnetic fields, we derive the spontaneous emission and spin polarization probabilities of atoms near a dielectric surface, and show the atom-surface distance dependence and refractive index dependence. Numerical evaluation for the 6P1/2-6S1/2 transition of a Cs atom indicates an increase in the efficiency of spin polarization by 30%.