Du wolof vers le français ou « Guelwaar » d’Ousmane Sembène : enjeux linguistiques et esthétiques

Contrairement à ses habitudes, l’écrivain cinéaste sénégalais Sembène a d’abord tourné son film Guelwaar avant d'écrire le roman (1996). En effet Sembène est toujours passé du texte littéraire au film. Le mandat, Mandabi ou encore Xala sont des exemples illustratifs. Il n’en est pas autrement du roman Niiwam adapté à l’écran par Clarence Thomas Delgado avec le film du même nom. Avec Guelwaar, il s’agit d’une adaptation littéraire d’une production cinématographique. Celle-ci passe non seulement par la cage de l’image, des sons, du visuel etc. au texte littéraire écrit, mais également par un changement de langues, du wolof, langue du film, au français, langue du roman. Les dialogues filmiques, qui relèvent de l’oralité sont en wolof et le texte littéraire français qui en découle, relève de l’écrit Cet article examine dès lors les enjeux linguistiques liés au changement de médium avec l’adaptation littéraire du roman. Ainsi il met l’accent sur les choix linguistiques de l’écrivain- cinéaste Sembène et sur le passage de l’écran à l’écrit, du wolof au français, de l’oral à l’écrit.

Impact of nonlocal response in plasmonic metasurfaces on four-wave mixing

We report the impact of nonlocal response in metallic nanostructures on four-wave mixing (FWM) process in nonlinear plasmonic metasurfaces which consist of Au nanostrips coupled with Au film spaced by an ultrathin dielectric film. When the dielectric film is linear and FWM only from the Au nanostructures, the FWM efficiency of around two orders of magnitude enhancement is obtained when the nonlocal effect of Au, not the traditionally local Drude model of Au, is considered. However, when the dielectric film is nonlinear and FWM from the Au nanostructures is negligible, the almost half FWM response from the nonlinear metasurface under the nonlocal, not the local model, of Au is confirmed. These results are both ascribed to the different local electric field distributions near the surface of Au nanostructures and in the gap at the local and nonlocal response of Au. The results have an important significance to design ultra-compacted integrated nonlinear optical devices or to explain the experimental measurements of nonlinear response involving plasmonic nanostructures of ultra-small gaps.

A Study on Fabrication Process of Gold Microdisk Arrays by the Direct Imprinting Method Using a PET Film Mold

In this study, an efficient nanofabrication process of metal microdisk arrays using direct imprinting was developed. This process was comprised of three steps; sputter etching on the quartz glass substrate, gold thin film deposition on an etched surface of a substrate, and transfer imprinting using a polyethylene terephthalate (PET) film mold on the Au thin film. A new idea to utilize a PET film mold for disk patterning by the nano transfer imprinting was examined. The PET film mold was prepared by thermally embossing the pillar pattern of a master mold on the PET film. The master mold was prepared from a silicon wafer. The PET film mold was used for transfer imprinting on a metal film deposited on a quartz substrate. The experimental results revealed that the PET film mold can effectively form gold micro-disk arrays on the Au film despite the PET film mold being softer than the Au film. This method can control the distribution and orientation of the nano-arrays on the disk. The plasmonic properties of the gold micro-disk arrays are studied and the absorbance spectrum exhibit depends on the distribution and orientation of gold micro-disk patterns. The nano-transfer imprinting technique is useful for fabricating metallic microdisk arrays on substrate as a plasmonic device.

Dynamic vortex Mott transition in triangular superconducting arrays

The proximity-coupled superconducting island arrays on a metallic film provide an ideal platform to study the phase transition of vortex states under mutual interactions between the vortex and potential landscape. We have developed a top-down microfabrication process for Nb island arrays on Au film by employing an Al hard mask. A current-induced dynamic vortex Mott transition has been observed under the perpendicular magnetic fields of $f$ magnetic flux quantum per unit cell, which is characterized by a dip-to-peak reversal in differential resistance $dV/dI$ vs. $f$ curve with the increasing current. The $dV/dI$ vs. $I$ characteristics show a scaling behavior near the magnetic fields of $f=\frac{1}{2}$ and $f=1$, with the critical exponents $\varepsilon$ of 0.45 and 0.3 respectively, suggesting different universality classes at these two fields.

Effect of Au substrate and coating on the lasing characteristics of GaAs nanowires

Optically pumped lasing from highly Zn-doped GaAs nanowires lying on an Au film substrate and from Au-coated nanowires has been demonstrated up to room temperature. The conically shaped GaAs nanowires were first coated with a 5 nm thick Al2O3 shell to suppress atmospheric oxidation and band-bending effects. Doping with a high Zn concentration increases both the radiative efficiency and the material gain and leads to lasing up to room temperature. A detailed analysis of the observed lasing behavior, using finite-difference time domain simulations, reveals that the lasing occurs from low loss hybrid modes with predominately photonic character combined with electric field enhancement effects. Achieving low loss lasing from NWs on an Au film and from Au coated nanowires opens new prospects for on-chip integration of nanolasers with new functionalities including electro-optical modulation, conductive shielding, and polarization control.

Performance Improvement of Residue-Free Graphene Field-Effect Transistor Using Au-Assisted Transfer Method

We report a novel graphene transfer technique for fabricating graphene field-effect transistors (FETs) that avoids detrimental organic contamination on a graphene surface. Instead of using an organic supporting film like poly(methyl methacrylate) (PMMA) for graphene transfer, Au film is directly deposited on the as-grown graphene substrate. Graphene FETs fabricated using the established organic film transfer method are easily contaminated by organic residues, while Au film protects graphene channels from these contaminants. In addition, this method can also simplify the device fabrication process, as the Au film acts as an electrode. We successfully fabricated graphene FETs with a clean surface and improved electrical properties using this Au-assisted transfer method.