Temporal shaping of femtosecond solitary pulses in photoionized media.
Femtosecond light pulses interacting with solids are studied. With a power close to the self-focusing threshold, an optical pulse evolves like a solitary wave with a temporal duration shrunk to a few femtoseconds through the defocusing action of multiphoton ionization. Self-steepening and space-time focusing are shown to form shock profiles, which do not prevent the pulse from keeping a shorter duration over one Rayleigh length. Theoretical estimates justify the key mechanisms leading to pulse compression, whose influence on the power spectra is finally discussed.
Ward
Hélène
H
Département de Physique Théorique et Appliquée, CEA-DAM/Ile de France, B.P. No. 12, F-91680 Bruyères-le-Châtel, France.
Bergé
Luc
L