Femtosecond Two-Photon Laser Photoelectron Microscopy

Abstract

It is shown that high-resolution photoelectron images (with a resolution of up to 3 nm for ultrasharp silicon tips) can be obtained for practically all materials when irradiating tips made of these materials by pulses of the second harmonic of a femtosecond Ti:sapphire laser. In addition to the images, absolute values of the two-photon external photoelectric effect for these tips also can be measured using this method. The first experimental realization of this two-photon femtosecond laser projection photoelectron microscope is presented, and corresponding data for silicon, diamond, and calcium fluoride tips are analyzed.