Photoelectron Spectroscopy of Laser Excited Surfaces Using Synchrotron Radiation

Abstract

For over a decade, laser pump-probe photoelectron spectroscopy (PES) has proven unique in its ability to determine the energy, momentum, and population dynamics of surface and near-surface excited states in solids.1,2 Practitioners most often generate the requisite probe UV pulse with laser upconversion techniques. The broader and continuous tunability of synchrotron radiation (SR) make it also an attractive source, albeit with reduced ultimate time resolution, and, in fact, SR is employed for time resolved spectroscopies spanning the far infrared to the hard x-ray regimes.3 We have developed a laser-pump, SR-probe PES system with nanosecond resolution at the National Synchrotron Light Source, and here we summarize results from GaAs, C60 films, and Si. This work anticipates specific areas where new photon probes, particularly femtosecond high harmonic generation4, UV-FEL’s, and 3rd generation SR sources, will find important applications.