  We employ dynamical mean-field theory to study the optical conductivity
$\sigma(\omega)$ of one hole in the Holstein-t-J model. We provide an exact
solution for $\sigma(\omega)$ in the limit of infinite connectivity. We apply
our analysis to Nd$_{2-x}$Ce$_x$CuO$_4$. We show that our model can explain
many features of the optical conductivity in this compounds in terms of
magnetic/lattice polaron formation.
