Evolution of dynamic localization regimes in coupled minibands

We consider the behaviour of two coupled symmetric electronic minibands in the presence of an AC intense field. Symmetric coupled minibands are realiz ed as dimerization procedures. The minibands are emulated by a tight-bindin g finite chain, whereas the interaction with an AC field is described by a time-independent Hamiltonian. We follow the evolution of dressed minibands, non perturbatively, in a wide frequency range. For one dimerization proced ure, a transition between both limits can be systematically followed and a dynamic breakdown is unambigously identified. The most striking effect that may occur is a field-induced analog of an insulator-metal transition due t o the suppression of a Peierls-like instability.