Epsilon-Near-Zero (ENZ), Mu-Near-Zero (MNZ), and Zero-Index Metamaterial (ZIM), and Plasmonic Interaction
Metamaterials with near-zero parameters exhibit unconventional properties in their interaction with electromagnetic and optical waves. We have been developing and investigating the concepts of supercoupling, tunneling, and energy squeezing through narrow channels and tight bends in waveguides. These results suggest that ENZ materials may have interesting potential applications in improving the transmission efficiency of waveguides with sharp bends or discontinuities, or in concentrating energy in a small subwavelength cavity with an enormous field enhancement. Moreover, the ENZ and ZIM materials may provide interesting possibilities in tailoring the wave fronts of arbitrary sources, since due to the 'static-like' behavior of the fields inside the ENZ and ZIM materials, the phase fronts tend to be conformal to the shape of the ENZ and ZIM objects, even for moderately sized objects. This property allows envisioning the possibility of controlling the phase fronts in the near-field. We have developed algorithms to synthesize a lens that transforms a given incoming wave front into another prescribed wave front. Furthermore, we have investigated methods for constructing matched zero-index material (with both epsilon and mu near zero) by embedding non-magnetic dielectric particles in an ENZ host medium. Matched zero-index metamaterials may help improving the transmission through waveguide bends or tight channels. In some waveguide scenarios, the scattering parameters may be completely independent of the specific arrangement of the inclusions and of the granularity of the crystal. Different metamaterial realizations were investigated, and it was shown that a properly loaded metallic waveguide near cut-off mimics in many ways the properties of such zero-index metamaterials.
For details regarding this image, please see, B. Edwards, A. Alu, M. Young, M. G. Silveirinha, and N. Engheta, "Experimental Realization of Metamaterial-Inspired Supercoupling and Energy Squeezing."
For details regarding this image, please see, M. Silveirinha, Nader Engheta, "Theory of Supercoupling, Squeezing Wave Energy, and Field Confinement in Narrow Channels and Tight Bends Using ε-Near-Zero Metamaterials", Physical Review B,
For details regarding this image, please see, A. Alu, M. G. Silveirinha, A. Salandrino, and N. Engheta, "Epsilon-Near-Zero Metamaterials and Electromagnetic Sources: Tailoring the Radiation Phase Pattern," Physical Review B