Linear and nonlinear spectroscopy at a cesium vapour/dielectric interface using a semiconductor laser

Linear and nonlinear spectroscopy on the Cs (6s2S12-6p2P32) transition at 852 nm is performed at a cesium vapour/dielectric interface. Two reflection phenomena are studied: selective reflection in a linear laser-atom interaction regime, and saturation spectroscopy in the evanescent wave. The spectral narrowing of selective reflection is observed as a function of angle in the range from near-normal incidence to the critical angle. The substantial narrowing which is observed for perpendicular incidence is found to decrease monotonically away from the surface normal. Studies of saturation spectroscopy beyond the critical angle demonstrate sensitive Doppler-free detection of near-surface atoms.