Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

We investigate the saturation of the optical absorption in graphene induced by ultrafast optical pulses. Within a microscopic theory, we study the momentum-, angle-, and time-resolved interplay of anisotropic excitation, carrier-carrier and carrier-phonon scattering and its influence on the saturation of absorption and transmission as a function of the input intensity. In agreement with recent experiments, we observe a linear regime for the intensity-dependence of the transmission at low pump fluences and a nonlinear saturation in the high excitation regime. Applying 10 fs-pulses we obtain a saturation fluence of approximately 6.5mJ/cm2. We demonstrate how the interplay of Pauli-blocking and intensity-dependent relaxation determines the saturation behavior.