Vavilov-Cherenkov effect in a driven resonant medium.

The Vavilov-Cherenkov effect in a dispersive and resonant absorbing medium is substantially modified by the presence of an external electromagnetic field. Depending on the field parameters and configuration we anticipate a remarkable increase of the emission yield at resonance. Our predictions are implemented by numerical estimates for cuprous oxide (Cu(2)O) where the yield turns out to be one to two orders of magnitude that obtained in the absence of the field.