Abstract

Angle resolved vuv photoemission spectroscopy (ARUPS) is widely used for band structure determination in crystalline solids. Photoemission energies and angles are directly related to electronic energies and vector momenta of occupied states in the solid. We have used vuv light produced by nonlinear conversion of picosecond laser pulses as a photoemission probe, to investigate optically excited solids using "pump-probe" delayed coincidence techniques. Electrons photoexcited above the Fermi level by picosecond visible or infrared laser pulses can be photoemitted during or immediately following the excitation. These electrons map out the structure of normally unoccupied bands. By varying the relative delay between the photoexcitation "pump" and photoemission "probe" pulses, electron dynamics can be directly observed.

© 1986 Optical Society of America