  We developed the theory of elastic electron tunneling through a potential
barrier driven by a strong high-frequency electromagnetic field. It is
demonstrated that the driven barrier can be considered as a stationary
two-barrier potential which contains the quasi-stationary electron states
confined between these two barriers. When the energy of an incident electron
coincides with the energy of the quasi-stationary state, the driven barrier
becomes fully transparent for the electron (the resonant tunneling). The
developed theory is applied to describe electron transport through a quantum
point contact irradiated by an electromagnetic wave.
