Abstract Self-compression of femtosecond pulses in noble gases with an input power close to the self-focusing threshold has been investigated experimentally and theoretically. It is demonstrated that either multiphoton ionization (MPI) or space--time focusing and self-steepening effects can induce pulse shortening, but they predominate at different beam intensities during the propagation. The latter effects play a key role in the final pulse self-compression. By choosing an appropriate focusing parameter, action distance of the space--time focusing and self-steepening effects can be lengthened, which can promote a shock pulse structure with a duration as short as two optical cycles. It is also found that, for our calculation cases in which an input pulse power is close to the self-focusing threshold, either group velocity dispersion (GVD) or multiphoton absorption (MPA) has a negligible influence on pulse characteristics in the propagation process.
Received: 26 March 2007
Revised: 18 September 2007
Accepted manuscript online:
PACS:
42.65.Jx
(Beam trapping, self-focusing and defocusing; self-phase modulation)
(Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.))
Fund: Project supported by the National
Basic Research Program of China (Grant No 2006CB806000), the
National Natural Science Foundation of
China (Grant Nos 60578049 and 10523003), and the Science and Technology
Commission of Shanghai Municipality of China (Gra
Cite this article:
Chen Xiao-Wei(陈晓伟), Zeng Zhi-Nan(曾志男), Dai Jun(戴君), Li Xiao-Fang(李小芳), Li Ru-Xin(李儒新), and Xu Zhi-Zhan(徐至展) Self-compression of femtosecond pulses in argon with a power close to the self-focusing threshold 2008 Chin. Phys. B 17 1826
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