  We have studied a one-dimensional channel with a wider, straight region
irradiated by an external electromagnetic field. In this system the interplay
between interference effects and resonance phenomena manifests itself and
provides a new behavior of conduction. We show that the transport properties of
the system can be affected by changing frequency and the amplitude of the
external field. We also show that for certain combinations of these parameters
electron transport through the system is complitely blocked.
