Abstract

The essential progress has been recently achieved in describing the interaction of atoms with superstrong laser field. The simple and clear semiclassical picture developed by Corkum¹ provides understanding of the role of quasi-free electron propagation in intense laser fields and shows the fundamental relations underlying basic experimental facts. Moreover, this model is easily generalized for the cases of elliptically polarized radiation and multicolor laser fields that have been recently proposed for the generation and measurement of subfemtosecond laser pulses.² We develop a semiclassical approach for describing the evolution of ionized electron in continuum that additionally takes into account Coulomb attraction of electron to parent ion, influence of laser magnetic field, relativistic electron mass increase, and electron wave-packet spreading with velocity 7 A/fs.³ These effects are described by the following equation:

© 1996 Optical Society of America