Determination of the spatial distribution of focused laser radiation from the shape of the Stark resonance profile

A method of determining the spatial distribution of focused laser radiation from the shape of the resonance maximum in the ion yield, which is due to the ionization of atoms via a resonance induced by the dynamic Stark effect, is proposed. This method gives the same results as the technique based on photometric measurements. The results of the measurements of the spatial distribution are compared with the results of calculation for focused Gaussian laser beams.