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We use specially designed plasmonic photodetectors to develop a new method for image differentiation that can produce edge-enhanced images without external optical elements and under incoherent illumination, unlike traditional optical spatial filters.

Angle-sensitive plasmonic photodetectors that can perform optical-domain spatial filtering operations are developed. The edge enhancement capabilities of these devices are demonstrated via computational imaging simulations based on their measured angular response.

We investigate the use of graphene plasmonic excitations for current-driven narrowband THz light emission. Device structures designed to promote critical coupling to free-space radiation are shown to be particularly effective for maximizing the output power.

Pronounced terahertz emission peaks originating from current-driven plasmonic oscillations in graphene nanoribbons are measured. The emission frequency can be tuned by design through the ribbon width and actively by varying the applied gate voltage.

We investigate the ability of gradient metasurfaces to promote directional light emission from an ensemble of dipole sources (colloidal quantum dots) in their near field. Well-collimated ouqrut beams along geometrically tunable directions are measured.

Pronounced plasmonic absorption features at terahertz frequencies are measured in large-area graphene sheets coupled to periodic arrays of metallic nanoparticles, and limitations on their tunability caused by carrier density inhomogeneities are investigated.