Multiphoton electron emission from Cu and W: An angle-resolved study

TLDR: The experimental results of multiphoton electron emission from Cu and W induced by 2-eV 100-fs laser pulses with s and p polarizations at incidence angles between 0 degrees and 85 degrees and different intensities show a third-order nonlinear photoemission process for Cu and a fourth-order behavior for W.

Abstract: The experimental results of multiphoton electron emission from Cu and W induced by 2-eV 100-fs laser pulses with $s$ and $p$ polarizations at incidence angles between 0\ifmmode^\circ\else\textdegree\fi{} and 85\ifmmode^\circ\else\textdegree\fi{} and different intensities are reported. The data show a third-order nonlinear photoemission process for Cu and a fourth-order behavior for W. For both metals the electron emission is higher for the polarization in the incidence plane, with a maximum value at the pseudo-Brewster angle, while the electron yield as a function of the incidence angle exhibits an unambiguous dependence on the bulk absorption coefficient and it can be accounted for on the basis of the Fresnel equations.