Abstract: High intensity nonresonant multiphoton ionization has been used in conjunction with time-of-flight mass spectrometry to perform highly sensitive, quantitative, chemical analysis. To achieve quantification of all elements simultaneously and obtain uniform detection efficiencies, all species, regardless of ionization potentials, should be saturated in a single, well-defined volume. To aid in this analysis, 3D potentials intensity distributions of high power laser beams were imaged at a nd near their focus. The cross-sectional intensity distributions of the fundamental and higher order harmonics of a 35-ps Nd:YAG laser beam showed near Gaussian profiles. For nonresonant multiphoton ionization of sputtered or gaseous atoms and molecules, high laser beam quality combined with high power density led not only to photo-ionization saturation of species with quite different ionization potentials, but also to sharply defined ionization volumes. Experiments were performed on the nonresonant multiphoton ionization of species from solid samples and from gaseous samples using well-characterized, high intensity laser beams. The result, driving relative sensitivity factors almost to unity, demonstrate quantitative compositional analysis. !18
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