TUNNELING THROUGH TIME-MODULATED BARRIERS - IS THERE A CROSSOVER FREQUENCY

Results are reported of extensive numerical simulations of the tunneling of a particle through a time-modulated barrier. It is demonstrated that the process of absorption and emission of modulation quanta depends sensitively on the modulation frequency and the modulation strength. The transmission coefficient develops a plateau at a crossover frequency which, for small to moderate modulation strength, corresponds to the frequency at which the energy of the first-order sideband becomes equal to the first resonance energy above the top of the barrier. © 1990.