Evidence of vectorial photoelectric effect on copper

Quantum efficiency (QE) measurements of single photon photoemission from a Cu(111) single crystal and a Cu polycrystal photocathodes, irradiated by 150 fs-6.28 eV laser pulses, are reported over a broad range of incidence angle, both in s and p polarizations. The maximum QE (similar or equal to 4x10(-4)) for polycrystalline Cu is obtained in p polarization at an angle of incidence theta=65 degrees. We observe a QE enhancement in p polarization which cannot be explained in terms of optical absorption, a phenomenon known as vectorial photoelectric effect. Issues concerning surface roughness and symmetry considerations are addressed. An explanation in terms of nonlocal conductivity tensor is proposed. (c) 2005 American Institute of Physics.