  The orbital Hall effect can generate currents of angular momentum more
efficiently than the spin Hall effect in most metals. However, so far, it has
only been understood as a steady state phenomenon. In this theoretical study,
the orbital Hall effect is extended into the time domain. We investigate the
orbital angular momenta and their currents induced by a femtosecond laser pulse
in a Cu nanoribbon. Our numerical simulations provide detailed insights into
the laser-driven electron dynamics on ultrashort timescales with atomic
resolution. The ultrafast orbital Hall effect described in this work is
consistent with the familiar pictorial representation of the static orbital
Hall effect, but we also find pronounced differences between physical
quantities that carry orbital angular momentum and those that carry charge. For
example, there are deviations in the time series of the respective currents.
This study lays the foundations for investigating ultrafast Hall effects in
confined metallic systems.
