Electron emission from metal surfaces excited by intense femtosecond pulses

Summary form only given. In order to understand quantitatively the electron yield and energy distribution and to develop a useful diagnostic technique, the authors present a combined experimental, analytical theory, and particle simulation investigation of femtosecond pulse induced electron emission from Al, Ag and W surfaces. Al [110], Ag [111], and W [100] samples in an ultrahigh vacuum chamber (P < 1 /spl times/ 10/sup -10/ torr) were excited by 90 fs, 2.0 eV laser pulses. In the analytical theory an effective space-charge potential barrier was added to the inner potential for the removal of an electron in the Richardson thermionic emission rate equation. Particle-in-cell computer simulation results confirm the analytic model. New emission mechanisms are shown to appear as a solid density plasma is formed and surface integrity is lost.