  We propose a simple method to spectrally resolve single-spins in a cold
atomic system, thus realizing single-spin addressing. This scheme uses a
dressing field with a spatially-dependent coupling to the atoms. We realize
this scheme experimentally using a linear chain of trapped ions that are
separated by $\sim3$ $\mu$m, dressed by a laser field that is resonant with the
micromotion sideband of a narrow optical transition.
