Pr. Zouheir SEKKAT

Mohamed V University, Morocco.

Surface enhanced absorption is a plasmonic effect parenting to surface enhanced fluorescence and Raman scattering, and it was clearly reported to occur in the infrared region of the spectrum of light. In this presentation, we unambiguously show that it also occurs in the visible region of the spectrum by using a dye; i.e. an azo-dye, which exhibits a good light absorption in that region, and gold nanoparticles, which act as plasmonic nanoantennas that capture and re-radiate light, when the azo-dyes and the nanoparticles are incorporated in the bulk of solid films of polymer. In such a configuration, it is possible to use a dye concentration much larger than that of the nanoparticles and absorption path lengths much larger than those of the molecularly thin layers used in surface enhanced effects studies. In addition, the dye undergoes shape and orientation change; i.e. isomerization and reorientation, upon polarized light absorption; and the observation of surface enhanced visible absorption is done by two separate experiments; i.e. UV-visible absorption spectroscopy and photo-induced birefringence, since the signals detected from both experiments are directly proportional to the extinction coefficient of the dye. Both the dye’s absorption and photoorientation are enhanced by the presence of the nanoparticles.

Pr. Zouheir SEKKAT : Professor at University Mohamed V, Department of Chemistry, Rabat, Cross-Appointed Professor of Osaka University, Japan and the director of the Optics and Photonics Centre of the Moroccan Foundation for Science, Innovation and Research (MAScIR). Sekkat completed his Master and PhD and Habilitation degrees, all from Paris-Sud University, Orsay. Sekkat did post-doctoral research stays Max-Planck Institute for Polymer Research, and at CPIMA jointly between the University of California-Davis and IBM-Almaden at San Jose, and Stanford. In 1999 Zouheir Sekkat joined Osaka University as an Associate Professor of Applied Physics. He is the leader of R&D projects in the fields of PV, biosensors, smart materials, 3D nanofabrication and Plasmonics. He is an author/co-author of more than 150 peer reviewed papers, co-owner of 10 patents in PV and Plasmonics. He is the President of the Moroccan Association of Nanotechnology, and has been awarded with different distinctions; he is a senior member of OSA and fellow of SPIE.