  We present a proof-of-principle experiment in which the population of an
atomic level is spatially localized using the technique of
electromagnetically-induced transparency (EIT). The key idea is to utilize the
sensitive dependence of the dark state of EIT on the intensity of the coupling
laser beam. By using a sinusoidal intensity variation (standing-wave), we
demonstrate that the population of a specific hyperfine level can be localized
much tighter than the spatial period.
