SELF-FOCUSING OF CHIRPED OPTICAL PULSES IN MEDIA WITH NORMAL DISPERSION

Citation
L. Berge et al., SELF-FOCUSING OF CHIRPED OPTICAL PULSES IN MEDIA WITH NORMAL DISPERSION, Journal of the Optical Society of America. B, Optical physics, 13(9), 1996, pp. 1879-1891
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Optics
ISSN journal
0740-3224
Volume
13
Issue
9
Year of publication
1996
Pages
1879 - 1891
Database
ISI
SICI code
0740-3224(1996)13:9<1879:SOCOPI>2.0.ZU;2-5
Abstract
The self-focusing of ultrashort optical pulses in a nonlinear medium w ith normal dispersion is examined. We demonstrate that chirping the pu lse initially can strongly increase the achievable peak intensity by c ompeting with the splitting of the pulse in the time domain. On the on e hand, we apply a variational procedure to Gaussian beams, leading to a reduced system of ordinary differential equations that describe the characteristic spatiotemporal evolutions of the chirped pulse. On the other hand, when the chirp induces a temporal compression of the puls e, it is shown by means of exact analytical estimates that a transvers e collapse can never occur. In the opposite situation, i.e., when the chirp forces the pulse to expand temporally while it shrinks in the tr ansverse diffraction plane, we display numerical evidence that chirpin g can generate highly spiky electric fields. We further describe the s plitting process that takes place near the self-focusing finite distan ce of propagation and discuss the question of the ultimate occurrence of a collapse-type singularity. (C) 1996 Optical Society of America.