PROPAGATION OF ULTRASHORT LIGHT-PULSES IN METALS

Reflection of powerful ultrashort light pulses on a plane surface of a metal or a semiconductor is considered. The pulses penetrate into the medium, in case the pulse duration is less than the relaxation time o f electrons. It is shown that such pulses can penetrate into a metal o r a semiconductor, even though the field spectral components lie below the plasma frequency. In this case the pulses will propagate without absorption.