We report the first observation of the Goos-Ha¨nchen
shift of a light beam incident on a metal surface. This phenomenon is
particularly interesting because the Goos-Ha¨nchen shift
for p polarized light in metals is negative and much bigger than the positive
shift for s polarized light. The experimental result for the measured shifts
as a function of the angle of incidence is in excellent agreement with
theoretical predictions. In an energy-flux interpretation, our measurement
shows the existence of a backward energy flow at the bare metal surface when
this is excited by a p polarized beam of light.Comment: The parer was published on Optics Express. The new version is
modified according to the reviewers suggestion