A High Efficiency Electron Energy Analyzer For Multiphoton Photoemission Spectroscopy

We report the use of a new, extremely efficient electron energy analyzer for recording high resolution electron spectra from multiphoton photoemission. The analyzer uses an electrostatic analogue of a parabolic mirror and has a collection solid angle in excess of 2pi sr with an energy resolution of 35 meV at 1.8 eV. Electron trajectories are collimated in an isochronic fashion and the energy is measured by time-of-flight. Furthermore, the analyzer has the potential to record accurately the angular distribution of the photoemitted electrons. We have used this detector to record the above threshold ionization spectra emitted in xenon using a 275 fsec, 616 nm, 2 x 10 sup (14) W/cm sup 2 laser pulse. Because of the very high collection efficiency of this new detector, the recorded spectra are found to be free from the effects of space charge.