August 22, 2014 - 11:00am - 12:00pmColumbia University Morningside Campus S.W. Mudd, Room 214Academic, Academic: LectureZeno Gaburro, Istituto Italiano di Tecnologia (IIT), Italy University of Trento, Italy - "Metasurface with Engineered Wavefront with Huygens, Fermat, Bragg, Friedel, and Fresnel Laws" ABSTRACT: We have recently proposed a metasurface that generalizes classical Snell law, based on phase discontinuities. Here, I provide an outlook on this structure from different and complementary points of view, referred to classical Huygens, Fermat, Bragg, Friedel and Fresnel laws. The structure shows a generalization of the concept of crystallographic systematic absence. As a result, the Friedel law of crystals completely breaks down. A novel concept of "metacrystal" can be introduced, where systematic absences can be originated from form factors of meta-atoms, in contrast with natural absences, which are based on structure factors only. Applications will be also presented. [N. Yu, P. Genevet, M.A. Kats, F. Aieta, J.P. Tetienne, F. Capasso and Z. Gaburro, Science 334, 333-337 (2011)].