  A graphene quantum dot under intense ac field and static low magnetic field
is investigated. From a tight-binding perspective, applying a Fourier-Floquet
transformation and renormalization process, we observe that graphene
-intrinsically anisotropic- reveals field polarization signatures in the
quasi-density of states. For the ac field polarized along the armchair
direction, the dressed electronic structure shows an emergent property: an ac
field induced quantum ring. This is inferred by the orientation-dependent
formation of a miniband of energy states periodically modulated with increasing
magnetic field, exactly analogous to the behavior of a quantum ring spectrum.
