Abstract:

I will give an overview of graphene plasmonics. Graphene is a two-dimensional, one-atom-thick layer of carbon atoms and permits surface excitations called surface plasmons. I will first discuss the optics of graphene using so-called semiconductor Bloch equations. This will lead to a characterization of graphene in terms of its surface conductivity. Subsequently, I will derive the dispersion relation of graphene surface plasmons and show some recent experimental results visualizing the plasmons. Graphene plasmons can potentially be used in a number of different ways, e.g., for two-dimensional wave front engineering and for tunable metamaterials. One of the advantages of graphene plasmons is that optical energy is highly localized very close to the graphene surface, giving rise to very sensitive refractive index sensors. I will end the first part of my lecture with a discussion of challenges related to graphene plasmonics. Graphene sheets can also be structured to obtain localized plasmon resonances and metasurfaces, of which I will discuss a number of examples. Here one of the advantages of graphene is its electric gate tunability. Finally, I will shortly describe some recent results about the nonlinear optics of graphene.

Bio:

Philippe Tassin teaches physics and optics and leads a research group on electromagnetic structured media at Chalmers University of Technology. He was born in Belgium and lived in several countries at both sides of the Atlantic Ocean. At the age of 17, he won a bronze medal at the International Chemistry Olympiad. Graduating in electrical engineering and applied physics, he obtained a M.Sc. degree and a Ph.D. degree from the Free University of Brussels, both summa cum laude. After his doctoral studies, he had postdoctoral appointments at Iowa State University and Ames Laboratory. Dr. Tassin is now an associate professor at Chalmers. His research interests encompass the physics of electromagnetic structured materials and systems, including metamaterials, plasmonics, and nanophotonics. His research has led to well-cited publications in scientific journals, including papers in Science, Nature Photonics, and Physical Review Letters, and he is frequently asked to deliver invited talks at international conferences. His research has been recognized by awards and fellowships from IEEE, SPIE, and the Flemish Research Foundation, and he recently received the BAEF Alumni Award from the Belgian-American Educational Foundation and the Frans Van Cauwelaert Award from the Royal Flemish Academy of Belgium for Science and the Arts. Dr. Tassin is also an editor of the journal “Photonics and Nanostructures.” He is a member of the Young Academy of Sweden and a senior member of SPIE and IEEE. He is a founding member and board member of the IEEE Photonics Sweden Chapter. He is also active in the promotion of science and technology to the public and to students.