55 research outputs found
Broadband negative refraction in stacked fishnet metamaterial
We demonstrate a scheme to utilize the stacked fishnet metamaterial for
all-angle negative refraction and subwavelength imaging within a wide frequency
range starting from zero frequency. The theoretical predictions are verified by
the finite-difference-in-time-domain (FDTD) numerical simulations. The
phenomena come from the negative evanescent coupling between the adjacent slab
waveguides through the breathing air holes perforated on metal layers.Comment: 8 pages, 4 figure
The Photonic Band theory and the negative refraction experiment of metallic helix metamaterials
We develop a theory to compute and interpret the photonic band structure of a
periodic array of metallic helices for the first time. Interesting features of
band structure include the ingenuous longitudinal and circularly polarized
eigenmodes, the wide polarization gap [Science 325, 1513 (2009)], and the
helical symmetry guarantees the existence of negative group velocity bands at
both sides of the polarization gap and band crossings pinned at the zone
boundary with fixed frequencies. A direct proof of negative refraction via a
chiral route [Science 306, 1353 (2004)] is achieved for the first time by
measuring Gooshanchen shift through a slab of three dimensional bona fide helix
metamaterial
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