Intensity-resolved multiphoton ionization: Circumventing spatial averaging

Abstract
A persistent problem in traditional high-field photoionization experiments is the intensity averaging caused by the use of focused laser beams. We show that it is possible to deconvolve ionization probabilities directly from data for experiments in which the detection volume is restricted. The inversion technique is outlined and as an example we apply it to multiphoton multiple-ionization measurements of xenon.