20 Jul
NTC researchers demonstrate the first double-negative metamaterial in the visible spectrum

NTC researches from the Universitat Politècnica de València have demonstrated experimentally a multilayer double-negative metamaterial working in the visible range. In collaboration with researchers from the King's College London, our team has built a three-layers fishnet metamaterial that exploits a second-order magnetic resonance to reach the visible regime. The low-loss nature of the employed magnetic resonance, together with the effect of the interacting adjacent layers, results in a figure of merit as high as 3.34. A wide spectral range of negative index is achieved, covering the wavelength region between 620 and 806 nm with only two different designs. This result has been published in Physical Review Letters.

metamaterial image

(a) Schematic of a fishnet metamaterial made up of three unit cells in the propagation direction. The overall number of layers is 7 (4 metal layers and 3 dielectric layers). (b) Top-view SEM image of the fabricated 3-unit-cell fishnet structure 3 (see Table I). (c) Detail of image in (b). (d) Detail of the fabricated 3-unit-cell fishnet structure 4.

Moreover, this result has been recognized as a milestone in optical metamaterials in a review written by Costas M. Soukoulis and Martin Wegener which is accepted for publication in Nature Photonics.

Low-Loss Multilayered Metamaterial Exhibiting a Negative Index of Refraction at Visible Wavelengths.
C. García-Meca, J. Hurtado, J. Martí, A.Martínez, W. Dickson and A. V. Zayats.
Physical Review Letters 106, 067402(1)-067402(2) (2011).