Recent rapid advancements in nanofabrication technologies have widened the realm of possibilities in nanophotonics, nonlinear and sub-wavelength optics. Realizing nonlinear optics in sub-wavelength scale paves the way for low cost integrated photonics. Ultra-high- Q photonic crystal nanocavities and nanostructured materials are examples of such structures. Specifically, the plasmonic nanostructures offer very small mode volume guaranteeing highly enhanced field intensity. The region of nonlinear interaction nonetheless is limited to the mode extend. This hinders the adoption of the bulk nonlinear mediums for frequency mixing applications. To circumvent this issue, the integration of the recently discovered 2D-materials and plasmonic nanostructures and extremely high Q photonic crystals is proposed.

Among 2D materials, graphene has been demonstrated to be optically nonlinear. The band structure of graphene differs substantially from that of the other known semiconductors. The honeycomb crystalline structure of graphene introduces the chiral quasiparticles obeying the Dirac equation. The symmetries of the graphene lattice entail significantly strong nonlinear optical properties making graphene a compelling candidate for integrated nonlinear optics. Though some metals may also exhibit strong nonlinearity, they are generally opaque and highly refractive. Unlike metals, graphene is almost transparent maintaining the optical structure intact.

Several graphene based integrated nonlinear optical devices for frequency down conversion and Terahertz signal generation, third harmonic generation and Plasmon enhanced optical bistability in graphene integrated plasmonic structures and photonic crystals have been proposed. The novel numerical analysis, quantum modeling and experimental characterizations are the topics of discussion in this seminar.


Seminar, June 6, 2016, 15:00. ICFO Seminar Room

Hosted by Prof. Frank Koppens