NB-Photonics Seminar with prof. Bjorn Maes
What: NB-Photonics seminar with prof. Bjorn Maes on Recent topics in nanophotonics: graphene plasmonics, parity-time symmetry and hyperbolic metamaterials.
When: Friday 4th November 2016, 11.30 to 13.00
Where: Auditorium 1 (1st floor), iGent, Campus Ardoyen – Zwijnaarde
** Registration is free but mandatory via this link **
Biosketch of speaker
Bjorn Maes received the engineering degree in applied physics in 2001 from Ghent University, Belgium. In 2005 he obtained the PhD degree from the Photonics Research Group at the same university. During 2005-2006 he spent one year as a postdoctoral associate at the Joannopoulos research group at MIT. In 2006-2010 he was an FWO postdoctoral fellow at the Photonics Research Group of Ghent University. In September 2010 he became professor at the Faculty of Science of the University of Mons. The focus of his group is on the modeling of photonic effects in thin-film, micro- and nano-scale structures. The group examines novel technologies, such as plasmonics and photonic crystals, to increase the efficiency of photovoltaic and LED devices.
Recent topics in nanophotonics: graphene plasmonics, parity-time symmetry and hyperbolic metamaterials
A graphene sheet was demonstrated to guide extremely confined modes in the mid-infrared range. It was realized that the properties of graphene are rapidly and drastically tunable. This catapulted graphene as a promising platform for compact and dynamic functionalities, an alternative for the traditional metals used in plasmonics.
In the field of parity-time symmetry a judicious balance between gain and loss is introduced. Very counterintuitively, these structures lead to modes that are perfectly propagating, so without exponential gain or loss, over a wide parameter range. When the gain/loss rate becomes too high, the modes suddenly change into the expected gain or loss behavior. Interesting features, such as unidirectional invisibility, are currently investigated in this new class of devices.
Finally, hyperbolic metamaterials lead to effective modal indices that are much higher than in traditional materials. This phenomenon stems from the specific shape of the dispersion contours: instead of the typical ellipses, the contours become hyperbolic, effectively leading to extremely high wavevectors. We will explore a mechanism leading to strongly confined cavities, specifically created by this hyperbolic behavior.