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A hybrid structure of a graphene nanomesh with the gold nanodisks is studied to enhance the light absorption by the localized surface plasmon resonance. From the reflection spectra of the visible range for graphene nanomesh samples without and with nanodisks, it is found that the absorption of graphene nanomesh structures is greatly enhanced in the presence of gold nanodisks around the resonance wavelength. Simulation results based on the finite-difference time-domain method support the experimental observations. This study demonstrates the potential of constructing graphene based photodetectors with a high light absorption efficiency and wavelength selectivity.

We implement a two-dimensional Maxwell's fish eye lens using a waveguide-based artificial dielectric. The Maxwell's fish eye lens consists of two metallic cylindrical plates sandwiching a free-space region, with the inner surface of one plate shaped into a hollow conical form. This lens has the capability to image terahertz beams from a source located at the edge (between the plates) to the diametrically opposite point on the edge, independent of the incident angle.

The field of metamaterials and the formalism of transformation optics have provided a prescription for constructing artificial dielectrics with unique properties such as light trapping and cloaking. Here, we describe a different approach to creating an inhomogeneous artificial medium, based on waveguide techniques, which does not rely on engineered subwavelength-scale components. We demonstrate a mirage effect in which an object several times larger than the selected wavelength is rendered invisible by bending a beam around it.

We demonstrate a broad-band low-loss THz near-field imaging technique based on a tapered parallel-plate waveguide. This technique works in a reflection geometry, which avoids the problem of low energy throughput due to the impedance mismatch and consequently limited spatial resolution, in the transmission geometry. Images reconstructed by the filtered-back-projection algorithm are able to resolve features of size ∼100 μm using radiation with an average wavelength of 1.5 mm.

We describe subwavelength-resolved measurements of the broadband terahertz field propagating inside a finite-width parallel-plate waveguide. We observe a transition in the spatial mode of the waveguide, in which the energy distribution shifts from the waveguide center to the edges with increasing frequency. This transition is surprisingly abrupt, and depends sensitively on the gap between the waveguide plates. These results may have important implications for a variety of terahertz experiments as well as in the design of optical systems and components in the visible and near-infrared regimes, which rely on plasmonic wave guiding.