Search results for "Kerr"

Incoherent solitons and condensation processes

2006

International audience; We study the nonlinear interaction of partially incoherent nonlinear optical waves. We show that, in spite of the incoherence of the waves, coherent phase effects may play a relevant role during the propagation, in contrast with the usual wave turbulence description of the interaction. These nonlinear phase effects may lead the system to unexpected processes of self-organization, such as condensation, or incoherent soliton generation in instantaneous response nonlinear media. Such self-organization processes may be characterized by a reduction of the non-equilibrium entropy, which violates the Boltzmann's H-theorem of entropy growth inherent to the wave turbulence th…

Measurement of high order Kerr refractive index of major air components: erratum

2010

A clarification is missing concerning the high order Kerr non-linearities deduced from our experimental data published in [Opt. Express 17, 13429-13434 (2009)]. Here, we rectify this omission by making explicit the distinction between cross-Kerr and Kerr effects, and by extrapolating the value of the nonlinear refractive index for the last effect. Since the occurrence of sign inversion in the Kerr effect is not affected, the overall report in [Opt. Express 17, 13429-13434] remains valid.

General approach to spatiotemporal modulational instability processes

2011

International audience; In this article, we derive the general exact solution of the modulation instability gain. The solution described here is valid for 1-D, 2-D, and 3-D cases considering any temporal response function of the medium and with possible higher order Kerr nonlinearities. In particular, we show that the gain induced by modulation instability is initial condition dependent, while the usual calculations do not lead to such a dependence. Applications for current and high-interest nonlinear propagation problems, such as 1-D optical fiber propagation with delayed Raman response and 2-D filamentation in gases, are investigated in detail. More specifically, we demonstrate that the 2-D …

Spectral dependence of purely-Kerr driven filamentation in air and argon

2010

5 pags, 4 figs.-- PACS number(s): 42.65.Jx, 42.65.Tg, 78.20.Ci. -- Publisher error corrected 27 September 2010, Erratum Phys. Rev. A 82, 039905 (2010): https://doi.org/10.1103/PhysRevA.82.033826

Numerical study of the Kerr solution in rotating coordinates

2016

International audience; The Kerr solution in coordinates corotating with the horizon is studied as a testbed for a spacetime with a helical Killing vector in the Ernst picture. The solution is numerically constructed by solving the Ernst equation with a spectral method and a Newton iteration. We discuss convergence of the iteration for several initial iterates and different values of the Kerr parameters.

Teollisuusneuvos Victor Kuusakoski (1918–1992)

2017

Tuhon ja rakkauden maisema

2014

Landscapes of loss and destruction: : Sámi elders’ childhood memories of the second world war

2019

The so-called Lapland War between Finland and Germany at the end of the Second World War led to a mass-scale destruction of Lapland. Both local Finnish residents and the indigenous Sámi groups lost their homes, and their livelihoods suffered in many ways. The narratives of these deeply traumatic experiences have long been neglected and suppressed in Finland and have been studied only recently by academics and acknowledged in public. In this text, we analyze the interviews with four elders of one Sámi village, Vuotso. We explore their memories, from a child’s perspective, scrutinizing the narration as a multilayered affective process that involves sensual and embodied dimensions of memory. ©…

Viiden vuosisadan jälkeen

2019

Kirja-arvostelu teoksesta Walter Isaacson: Leonardo da Vinci, suom. Tero Valkonen, Bazar 2019, 592 s. nonPeerReviewed

Toward a wave turbulence formulation of statistical nonlinear optics

2012

International audience; During this last decade, several remarkable phenomena inherent to the nonlinear propagation of incoherent optical waves have been reported in the literature. This article is aimed at providing a generalized wave turbulence kinetic formulation of random nonlinear waves governed by the nonlinear Schrodinger equation in the presence of a nonlocal or a noninstantaneous nonlinear response function. Depending on the amount of nonlocal (noninstantaneous) nonlinear interaction and the amount of inhomogeneous (nonstationary) statistics of the incoherent wave, different types of kinetic equations are obtained. In the spatial domain, when the incoherent wave exhibits fluctuatio…