David Keene

Hyperbolic resonances of metasurface cavities

We propose a new class of optical resonator structures featuring one or two metasurface reflectors or metacavities and predict that such resonators support novel hyperbolic resonances. As an example of such resonances we introduce hyperbolic Tamm plasmons (HTPs) and hyperbolic Fabry-Perot resonances (HFPs). The hyperbolic optical modes feature low-loss incident power re-distribution over TM and TE polarization output channels, clover-leaf anisotropic dispersion, and other unique properties which are tunable and are useful for multiple applications.

Ultimately Thin Metasurface Wave Plates

Optical properties of a metasurface which can be considered a monolayer of uniaxial metamaterials - parallel-plate and nanorod arrays – are investigated. It is shown that such metasurface acts as an ultimately thin sub-100 nm wave plate. This is achieved via an interplay of epsilon-near-zero and epsilon-near-pole behavior along different axes in the plane of the metasurface allowing for extremely rapid phase difference accumulation in very thin metasurface layers. These effects are shown to not be disrupted by non-locality and can be applied to the design of ultrathin wave plates, Pancharatnam-Berry phase optical elements and plasmon-carrying optical torque wrench devices.

Plasmon drag effect in plasmonic metasurfaces

Plasmon drag effect (PLDE) is the generation of dc electric currents associated with the excitation and propagation of surface plasmon polaritons in metal nanostructured systems. In order to better understand the mechanism of the effect and explore its properties, we experimentally study PLDE in the dependence on light intensity, wavelength and angle of incidence in hyperbolic metasurfaces of different periodicity and surfaces with random roughness. The results are discussed theoretically in a frame of the hydrodynamic loss approach.

Probing plasmonic electro-magnetic environment with Eu3+

We use spontaneous emission of Eu3+ ions as a spectroscopic tool to probe modifications of optical fields in close vicinity of metal and under the conditions of the optically-induced magnetic resonance. We reveal strictly different behavior of electric and magnetic dipole emission in a simple microscope setup, and also discuss the results theoretically.