Abstract

Recently, we have proposed two avenues to generating ultrashort (potentially, subfemtosecond) and intense (up to atomic fields) nonoscillating pulses: a high-repetition train of such pulses can be produced in multicomponent stimulated Raman scattering [1], and a single pulse ("electromagnetic bubble" -- EMB) or several of them can result [2,3] from the propagation of an initially broad unipolar pulse (half-cycle pulse -- HCP [4]) in an appropriate nonlinear medium. Such pulses could cause a substantial "shake-up" excitation or ionization of an atomic system within the time much smaller than any characteristic time of the system. These "superpulses" would open a new chapter in nonlinear optics and atomic and molecular physics, both as a new probing tool and a source of new effects. In the present paper, we consider one of them: backward and multi-echo field ionization [5].

© 1997 Optical Society of America