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We ask the question "what happens to Bloch waves in gratings synthetically moving at near the speed of light?". First we define a constant refractive index (CRI) model in which Bloch waves remain well defined as they break the light barrier, then show their dispersion rotating through 360° from negative to positive and back again. Next we introduce the effective medium approximation (EMA) then refine it into a 4-wave model which proves to be highly accurate. Finally using the Bloch waves to expand a pulse of light we demonstrate sudden inflation of pulse amplitude combined with reversal of propagation direction as a luminal grating is turned on. [ABSTRACT FROM AUTHOR]

A study was conducted to analyze in detail the concepts of optical nanoinsulators and nanoconnectors in optical nanocircuits. The findings demonstrated the critical role of nanoinsulators and nanoconnectors in minimizing the coupling between adjacent optical nanocircuit elements and in properly connecting different branches of the nanocircuit.

Using an effective medium approach, we describe how, by combining mercury-cadmium-telluride semiconductor alloys with band gap energies of opposite signs, it may be possible to design a superlattice where the electrons have isotropic zero-effective mass and a single valley linear energy-momentum dispersion. We demonstrate that, because of the zero-mass property, the superlattice may have a strong nonlinear optical response. [ABSTRACT FROM AUTHOR]

It is theoretically demonstrated that electron states in semiconductors or graphene can be perfectly transmitted through a complementary material with dual properties, independent of the angle of incidence. It is shown that such complementary material may also provide a strong spatial derealization of bounded electronic states, changing dramatically the confinement of the wave function, and acting effectively as a lens for the probability wave. The results are the electron analogue of a perfect lens for electromagnetic waves proposed in an earlier work. [ABSTRACT FROM AUTHOR]

We develop an effective medium approach to characterize the propagation of matter waves in periodic structures, such as graphene or semiconductor superlattices. It is proven that the time evolution of the states that are not more localized in space than the characteristic period of the structure can be described exactly through an effective Hamiltonian, and that the electronic band structure of the system can be exactly determined from the effective Hamiltonian. As an illustration of the application of the method, we characterize the mesoscopic response of graphene superlattices. It is shown that these structures may be described using simply two effective parameters: a dispersive potential, and an anisotropy tensor that characterizes the pseudospin. Our model predicts that a graphene superlattice characterized by an indefinite anisotropy tensor--such that the eigenvalues of the tensor have opposite signs--may permit the perfect tunneling of all the stationary states with a specific value of the energy when it is paired with a dual graphene superlattice with a positive definite anisotropy tensor. [ABSTRACT FROM AUTHOR]

Here, we investigate the physical mechanisms that may enable squeezing a complex electromagnetic Held distribution through a narrow and/or partially obstructed region with little amplitude and phase distortions Following our recent works, such field manipulations may be made possible by a procedure in which the incoming wave is first "sampled" "pixel by pixel" using an array of metallic waveguides, and in a second step the energy corresponding to each individual pixel is "squeezed" through a very narrow channel filled with a permittivity-near-zero material. In this work, we study in detail these processes in scenarios in which the electromagnetic wave is compressed along a single direction of space and present theoretical models that enable the analytical modeling of such phenomena. Full-wave results obtained with an electromagnetic simulator, demonstrate the possibility of compressing an incoming wave several folds through ultranarrow channels filled with silicon carbide. The "sampling and squeezing" concept may enable unparalleled control of electromagnetic waves in the nanoscale. [ABSTRACT FROM AUTHOR]

In a spatially dispersive medium, the electric dipole moment of an inclusion cannot be related to the macroscopic electric field through a local relation. Several recent works have emphasized the role of spatial dispersion in wire media, and demonstrated that arrays of parallel metallic wires may behave very differently from a uniaxial local material with negative permittivity. Here, we investigate the effect of spatial dispersion on reflection properties of the mushroom structure introduced by Sievenpiper, based on local and nonlocal homogenization methods. The objective of this paper is to clarify the role of spatial dispersion in the mushroom structure and demonstrate that, under some conditions, it is suppressed. The metamaterial substrate, or meta-surface is modeled as a wire medium covered with an impedance surface. Surprisingly, it is found that, in such a configuration, the effects of spatial dispersion may be nearly suppressed when the slab is electrically thin, and that the wire medium can be modeled very accurately using a local model. [ABSTRACT FROM AUTHOR]