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PublicationExperimental Verification of Plasmonic Cloaking at Microwave Frequencies with Metamaterials(2009-10-06) Edwards, Brian; Silveirinha, Mário G.; Engheta, Nader; Alù, AndreaPlasmonic cloaking is a scattering-cancellation technique based on the local negative polarizability of metamaterials. Here we report its first experimental realization and measurement at microwave frequencies. An array of metallic fins embedded in a high-permittivity fluid has been used to create a metamaterial plasmonic shell capable of cloaking a dielectric cylinder, yielding over 75% reduction of total scattering width. PublicationReflectionless Sharp Bends and Corners in Waveguides Using Epsilon-Near-Zero Effects(2009-02-18) Edwards, Brian; Alù, Andrea; Engheta, Nader; Silveirinha, M. G.Following our recent theoretical and experimental results that show how zero-permittivity metamaterials may provide anomalous tunneling and energy squeezing through ultranarrow waveguide channels, here we report an experimental investigation of the bending features relative to this counterintuitive resonant effect. We generate the required effectively zero permittivity using a waveguide operating at the cutoff of its dominant mode, and we show how sharp and narrow bends may be inserted within the propagation channel without causing any sensible reflection or loss and without affecting its tunneling properties. PublicationNonlinear Control of Tunneling Through an Epsilon-Near-Zero Channel(2009-06-29) Powell, David A.; Edwards, Brian; Alù, Andrea; Vakil, AshkanThe epsilon-near-zero (ENZ) tunneling phenomenon allows full transmission of waves through a narrow channel even in the presence of a strong geometric mismatch. Here we experimentally demonstrate nonlinear control of the ENZ tunneling by an external field, as well as self-modulation of the transmission resonance due to the incident wave. Using a waveguide section near cut-off frequency as the ENZ system, we introduce a diode with tunable and nonlinear capacitance to demonstrate both these effects. Our results confirm earlier theoretical ideas on using an ENZ channel for dielectric sensing and their potential applications for tunable slow-light structures.