Nonlinear Forced Response of Plasmonic Nanostructures.

Incorporating optical surface waves in nonlinear processes unlocks unique and sensitive nonlinear interactions wherein highly confined surface states can be accessed and explored. Here, we unravel the rich physics of modal-nonmodal state pairs of short-range surface plasmons in thin metal films by leveraging "dark nonlinearity"-a nonradiating nonlinear source. We control and observe the nonlinear forced response of these modal-nonmodal pairs and present nonlinearly mediated direct access to nonmodal plasmons in a lossless regime. Our study can be generalized to other forms of surface waves or optical nonlinearities, toward on-chip nonlinearly controlled nanophotonic devices.

Perfect Lensing by a Single Interface: Defying Loss and Bandwidth Limitations of Metamaterials.

Loss is known to be detrimental for achieving perfect focusing with the passive perfect lens designs suggested thus far, and it is believed to pose a fundamental barrier. We show that perfect lensing can be achieved with actual lossy left-handed metamaterials, without a need for gain or nonlinearity. The proposed loss-immune perfect lens is composed of a single interface between a conventional dielectric material on the source side and a lossy left-handed material on the image side. Its immunity to material loss was derived analytically using three complementary methodologies, confirming perfect lensing with point-to-point accuracy and shedding light on the underlying focusing mechanism. This result provides a new road map for practical realization of a near-field camera based on the single-interface lens design.

Competing coupled gaps and slabs for plasmonic metamaterial analysis.

Layered medium comprised of metal-dielectrics constituents is of much interest in the field of metamaterials. Here we introduce a novel analysis approach based on competing coupled structures of plasmonic gaps (MIM) and slabs (IMI) for the detailed comprehension of the band structure of periodic metal-dielectric stacks. This approach enables the rigorous identification of many interesting features including the intersections between plasmonic bands, flat or negative band formation, and the field symmetry of the propagating modes. Furthermore - the "gap-slab competition" concept allows us to develop design tools for incorporating desired dispersion properties of both gap and slab modes into the stack's band structure, as well as effects of finite stack termination.

Circular motion of electromagnetic power shaping the dispersion of Surface Plasmon Polaritons.

A circular zero-time-averaged power component, coupling the forward (dielectric) and backward (metal) power channels of Surface Plasmon Polaritons (SPPs), is shown to be the core ingredient for the slow-light characteristic of SPPs at the surface plasmon frequency, for both a lossless and lossy metal. Additional slow-light regimes emerging in configurations where few SPPs are strongly coupled, such as in a narrow plasmonic gap and slab, forming local extrema of the dispersion curve (branch points for positive and negative index branches), are also propelled by the circular motion of the plasmonic power.