Photoemission from Mg irradiated by short pulse ultraviolet and visible lasers

Quantum efficiency of diamond turned magnesium was measured with low intensity, 266 nm, 12 ps, p-polarized radiation for various incident angles. The optimum quantum efficiency of 3×10−4 was obtained with p-polarized light incident close to Brewster’s angle where the absorption is maximum. Investigations of the field dependence of the yield indicate that application of a high surface field is expected to lower the surface barrier by Schottky effect and increase the quantum efficiency further. Measurements of the electron yield with 632 nm radiation of 300 fs pulse duration indicate that at intensities exceeding 20 MW/cm2, the electric field due to the laser may become important and start contributing to the electron emission. Autocorrelation measurements at low intensities with this wavelength indicate that the electron emission is prompt.