  We study the carrier dynamics in epitaxially grown graphene in the range of
photon energies from 10 - 250 meV. The experiments complemented by microscopic
modeling reveal that the carrier relaxation is significantly slowed down as the
photon energy is tuned to values below the optical phonon frequency, however,
owing to the presence of hot carriers, optical phonon emission is still the
predominant relaxation process. For photon energies about twice the value of
the Fermi energy, a transition from pump-induced transmission to pump-induced
absorption occurs due to the interplay of interband and intraband processes.
