  The endohedral fullerene Er3N@C80 shows characteristic 1.5 micron
photoluminescence at cryogenic temperatures associated with radiative
relaxation from the crystal-field split Er3+ 4I13/2 manifold to the 4I15/2
manifold. Previous observations of this luminescence were carried out by
photoexcitation of the fullerene cage states leading to relaxation via the
ionic states. We present direct non-cage-mediated optical interaction with the
erbium ion. We have used this interaction to complete a
photoluminescence-excitation map of the Er3+ 4I13/2 manifold. This ability to
interact directly with the states of an incarcerated ion suggests the
possibility of coherently manipulating fullerene qubit states with light.
