Abstract

We are studying the multiple ionization of gases by using an ultrashort-pulse laser system being developed at this laboratory. Ultrafast ionization of atoms and ions by very intense laser pulses at optical frequencies is still an exploratory dynamic regime. At sufficiently high intensities the peak laser fields approach levels similar to the Coulomb binding fields. Ionization rates can exceed the laser frequency, and the ionization process may also be considered with an optical field description. This is a high-frequency analog of dc field ionization and can be better isolated when appropriately high optical fields are attained within ultrashort rise times.

© 1991 Optical Society of America