The nonlinear photoeffect of gold was investigated with a sub-picoseco
nd laser at a photon energy of 2.57 eV. Absorption of a minimum of two
photons is required to produce photoelectrons. The measured electron
spectra display a broad continuum resulting from absorption of additio
nal photons. The intensity dependence was examined by means of the pum
p-probe technique and yields the order of non-linearity for the invest
igated process.