Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

We discuss pump-probe experiments on multilayer graphene over a wide range of photon energies (10-250 meV), hereby unveiling the relevant electronic relaxation mechanisms. A slowing down is observed for smaller photon energies and lower temperature, in accord with microscopic calculations. Remarkably we observe a sign change of the probe signal, when the photon energy becomes smaller than twice the Fermi energy. This crossover from induced bleaching to induced absorption is related to the interplay between inter- and intraband absorption. Applying an additional magnetic field we have recently measured the relaxation dynamics between Landau levels, showing a strong dependence on the circular polarization of the light.