Abstract
We report what is to our knowledge the first experimental observation of the deflection of a light beam at the interface of a glass window and Cs vapor in a transverse-magnetic field. The effect is detected as a parallel displacement of a laser beam transmitted through a Cs vapor cell. We measured its dependence on field strength and laser power near the D2 line. The observed displacement (≈30 nm for 50 G) corresponds to a deflection angle of 1.5 μrad. The experimental values are in reasonable agreement with a model that relates the effect to the magnetic circular dichroism. At moderate power levels, nonlinear contributions enhance the effect by several orders of magnitude.