  For autonomous systems it is well known how to extract tunneling
probabilities from wavepacket calculations. Here we present a corresponding
approach for periodically time-dependent Hamiltonians, valid at all
frequencies, field strengths, and transition orders. After mapping the
periodically driven system onto a time-independent one with an additional
degree of freedom, use is made of the correlation function formulation of
scattering [J. Chem. Phys. {\bf 98}, 3884 (1993)]. The formalism is then
applied to study the transmission properties of a resonant tunneling double
barrier structure under the influence of a sinusoidal laser field, revealing an
unexpected antiresonance in the zero photon transition for large field
strengths.
