Light magnetized raspberries
The invisibility cloak will likely exist in the future, either thanks to Harry Potter’s magic, or thanks to science. In that latter case, it will probably consist of a fabric, in which nanometric objects with a specific response to light are woven, rather than textile fibers. Many interesting optical properties stem from a very small-scale structuration of certain materials either natural (opals, nacre, beetle carapace) or man-made (the bright red or yellow colors in cathedral tinted-windows are due to inclusions of metallic nanoparticles). Recent breakthroughs in several scientific disciplines working together (electromagnetic theory, nanofabrication, chemistry, physico-chemistry, optics) have enabled scientists to take critical steps towards extraordinary properties. This is what a collaboration between a British team, a CRPP team and three other Bordeaux teams, within the AMADEus labex, have demonstrated and published recently in Materials Horizons1. The authors have assembled metallic satellite nanoparticles around a dielectric core nanoparticle, following a pattern called the “plasmonic raspberry”. According to our static light scattering measurements, the resulting nanoresonator reacts to light as if it were magnetized by the magnetic field of the light wave1. The plasmonic raspberries were then assembled, using a microfluidic technology, into a compact material, which also reacts to illumination as if it were magnetized2 by the magnetic field of the light beam. Controlling such a response, which does not exist in natural materials, is a powerful new route to monitor the refractive indices and therefore control the path of light in artificial materials.
Link to the paper (for subscribers only) : http://pubs.rsc.org/en/content/arti...
Resonant isotropic optical magnetism of plasmonic nanoclusters in visible light, V. Ponsinet, P. Barois, S.M. Gali, P. Richetti, J.B. Salmon, A. Vallecchi, M. Albani, A. Le Beulze, S. Gomez-Grana, E. Duguet, S. Mornet and M. Treguer-Delapierre, Phys. Rev. B : Condens. Matter Mater. Phys., 92, 220414(R) (2015), DOI : 10.1103/PhysRevB.92.220414
Hierarchical self-assembly of a bulk metamaterial enables isotropic magnetic permeability at optical frequencies, S. Gomez-Graña, A. Le Beulze, M. Treguer-Delapierre, S. Mornet, E. Duguet, E. Grana, E. Cloutet, G. Hadziioannou, J. Leng, J.-B. Salmon, V. G. Kravets, A. N. Grigorenko, N. A. Peyyety, V. Ponsinet, P. Richetti, A. Baron, D. Torrent, P. Barois, Materials Horizons (2016)
DOI : 10.1039/c6mh00270f, in press