Search results for " Nonlinear"

Statistical mechanics of nonclassic solitonic structures-bearing dna system

2011

International audience

Supratransmission dans une ligne électrique de Klein-Gordon

2017

National audience; Nous présentons une ligne électrique dont la tension obéit aux équations de Klein-Gordon d’ordre 5afin d’en étudier les propriétés de transmission. Nous focalisons sur la transmission d’énergie en bande interdite,c’est à dire lorsque le système est excité en dehors de sa bande passante. Nous avons pu expérimentallement mettreen évidence que lorsque l’amplitude de l’excitation excède un seuil, le système génére des modes non linéaires deforte amplitude via le phénomène de supratransmission.

Energy transmission in the gap of nonlinear media triggered by deterministic and stochastic driving

2016

International audience; These past years, a growing interest has been devoted to the analysis of the response of nonlinearmedia to various excitations wether random or deterministic in order to better characterizetheir transmission properties [1, 2, 3]. Especially, since the introduction of the concept of soliton,the development of nonlinear electrical transmission lines has provided an efficient tool toexperimentally investigate the behaviour of these nonlinear waves [4]. Recently, some effortshave focused on the energy transmission in the gap of media obeying to equations deriving fromthe nonlinear Schr¨odinger model [5, 6]. Indeed, Geniet and Leon have shown that such nonlinearsystems, w…

Integrable Systems and Factorization Problems

2002

The present lectures were prepared for the Faro International Summer School on Factorization and Integrable Systems in September 2000. They were intended for participants with the background in Analysis and Operator Theory but without special knowledge of Geometry and Lie Groups. In order to make the main ideas reasonably clear, I tried to use only matrix algebras such as $\frak{gl}(n)$ and its natural subalgebras; Lie groups used are either GL(n) and its subgroups, or loop groups consisting of matrix-valued functions on the circle (possibly admitting an extension to parts of the Riemann sphere). I hope this makes the environment sufficiently easy to live in for an analyst. The main goal is…

projet FOURIER - Fibre et optique ultra rapide pour l’investigation d’événements rares

2023

Higher-order Kerr terms allow ionization-free filamentation in gases

2010

International audience; We show that higher-order nonlinear indices (n4 , n6 , n8 , n10) provide the main defocusing contribution to self-channeling of ultrashort laser pulses in air and Argon at 800 nm, in contrast with the previously accepted mechanism of filamentation where plasma was considered as the dominant defocusing process. Their consideration allows to reproduce experimentally observed intensities and plasma densities in self-guided filaments.

High-order Kerr nonlinearity of air calibrated with transient molecular alignment

2009

Talk given by O. Faucher; International audience; Nonlinear electronic Kerr index of the major air constituents has been measured up to high order terms using transient molecular alignment as a reference. Sign reversal associated to negative nonlinearity is observed above a pulse intensity of 26 TW/cm^2.

Spatiotemporal optical solitons in nonlinear dissipative media: From stationary light bullets to pulsating complexes

2007

Nonlinear dissipative systems display the full (3+1) D spatiotemporal dynamics of stable optical solitons. We review recent results that were obtained within the complex cubic-quintic Ginzburg-Landau equation model. Numerical simulations reveal the existence of stationary bell-shaped (3+1) D solitons for both anomalous and normal chromatic dispersion regimes, as well as the formation of double soliton complexes. We provide additional insight concerning the possible dynamics of these soliton complexes, consider collision cases between two solitons, and discuss the ways nonstationary evolution can lead to optical pattern formation. © 2007 American Institute of Physics.

Statistical analysis of pulse propagation driven by polarization-mode dispersion

2002

International audience; The linear propagation of pulses driven by random polarization-mode dispersion is considered. Analytical expressions are derived for the probability-density functions of the pulse width, timing displacement, and degree of polarization. The study is performed in Stokes space, and frequency correlation between modes is shown to play an important role in it.

50 years of fiber solitons

2023

The study of temporal solitons has revolutionized fiber optics, yielded new classes of ultrafast laser and opened multiple interdisciplinary applications.