Abstract

Recent advances in high power laser development have enabled field strengths comparable to the atomic binding field to be generated. This experimental achievement has stimulated considerable interest in the study of the nature of multiphoton processes. Previously reported results of photoelectron spectra using 10 ps, 193 nm radiation¹ have shown that the photoionization mechanism for the low charge states is largely a stepwise process and the threshold intensities required to produce the charge states are in reasonable agreement with the Keldysh model. In addition, the effect of the ponderomotive potential in suppressing the lowest order ionization channel was observed.

© 1986 Optical Society of America