  Non-Markovian effects arising in open quantum systems evolution have been a
subject of increasing interest over the past decade. One of the most appealing
features of non-Markovianity (NM) is that it captures scenarios where loss of
information and coherence are reversible, and thus a temporary backflow of
information from the environment to the system is possible. In this work we
study the interplay between the degree of non-Markovianity and the action of
time-dependent control fields in an open two-level quantum system. We find that
periodical modulation of a field acting solely on the system can greatly
enhance the degree of non-Markovianity with respect to the undriven case. We
show that this effect is present only when the coupling between system and
environment is weak. Remarkably, the enhancement disappears at strong coupling,
which is usually the regime where non-Markovian effects are expected to be more
pronounced.
