  We report a linear-scaling numerical method for exploring nonequilibrium
electron dynamics in systems of arbitrary complexity. Based on the Chebyshev
expansion of the time evolution of the single-particle density matrix, the
method gives access to nonperturbative excitation and relaxation phenomena in
models of disordered materials with sizes on the experimental scale. After
validating the method by applying it to saturable optical absorption in clean
graphene, we uncover that disorder can enhance absorption in graphene and that
the interplay between light, anisotropy, and disorder in nanoporous graphene
might be appealing for sensing applications. Beyond the optical properties of
graphene-like materials, the method can be applied to a wide range of
large-area materials and systems with arbitrary descriptions of defects and
disorder.
