Microscopic lens effect in photoelectron imaging spectroscopy

Abstract

The photoelectron imaging spectrometer has been used to investigate the resonant multiphoton ionization of xenon and hydrogen. Under certain conditions, extremely sharp unexpected features appear in the photoelectron images. It is shown that these features are produced by the residual ions acting as a microscopic lens that distorts the trajectories of the photoelectrons. The relevance of this phenomenon in zero electron kinetic energy spectroscopy and in experiments concerned with angular distribution measurements in strong-laser-field multiphoton ionization or in the photodetachment microscope is discussed.