  We report on the optical spectroscopy of the spin of two magnetic atoms (Mn)
embedded in an individual quantum dot interacting with either a single
electron, a single exciton and single trion. As a result of their interaction
to a common entity, the Mn spins become correlated. The dynamics of this
process is probed by time resolved spectroscopy, that permits to determine the
optical orientation time in the range of a few tens of $ns$. In addition, we
show that the energy of the collective spin states of the two Mn atoms can be
tuned through the optical Stark effect induced by a resonant laser field.
