CONTROLLING THE CHARACTERISTICS OF LASER LIGHT: Propagation of ultrashort light pulses in metals

This paper analyzes the reflection of intense ultrashort pulses from a plane metal or semiconductor surface and the penetration of these pulses into the medium when the pulse length is shorter than the electron relaxation time. Light pulses of this sort can penetrate into metals or semiconductors even if spectral components of the field lie below the plasma frequency. They then propagate without absorption.