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(a) The unit cell. Lattice constants , Au strip and central layer thicknesses , strip width , and spacer thickness . Gold strips and the central metallic layer are embedded in a polymer dielectric (cyclotene). (b) Atomic force microscope profile after planarization by the cured polymer on top of the Au grating pattern. The peak-to-valley roughness is 4.3 nm. Inset: The atomic force microscope image of the grating covered by the cured polymer where the white line transverse to strips shows the cross section analyzed, and the marks correspond to their positions in (b). (c) SEM image of a completed structure. Inset: Top strips on top of the bottom strips at the edge of the pattern showing the alignment between them where the central metallic layer is absent.
(a) and (b) Transmission spectra for the NIM layers in Fig. 1. Continuous lines are experimental data; open circles are simulated results for structures with metal layer thicknesses , top and bottom spacer thicknesses and , respectively. Strip widths: (a) and (b) . [(c)–(f)] Calculated band structure of the dominant Bloch mode assuming the geometrical parameters of (a) and (b), respectively. Transmission spectra and band structure of the same geometrical parameters are in the same column.
(a) Time averaged power flow for a prism at an incident wavelength of . The dark background corresponds to nearly zero power flow. Disorder is introduced into the metal strip positions in the prism. Two far-field beams (1 and 2) are observed. (b) Comparison of effective indices extracted from numerical simulations and band structure calculations. Circles: Index calculated from the band structure of unit cell in Fig. 1(a). Squares: negative refraction. Triangles: diffraction. The horizontal line represents the angular position parallel to the hypotenuse. Inset: Amplitude of the magnetic field of the Bloch mode of the unit cell in Fig. 1(a) at a wavelength of . Darker shade represents a larger field.
Nominal and experimentally determined dimensions of the negative index material structure in Fig. 1. Relative fabrication errors of the various dimensions are shown.
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