All successful designs for negative refractive index in the optical range have so far used the idea of creating a negative magnetic permeability by means of the excitation of asymmetric currents ...

and the result is an important step towards the creation of double-negative negative-index metamaterials (DN-NIMs) that operate in the visible range. Fishnet metamaterial Naturally occurring materials ...

According to Fig. 4a, the NIM remains active within a spectral range between 722 and 738 nm, and the refractive index is negative in a broader range, between 720 and 760 nm. Far-field ...

in that it can handle light with any polarization over a broad range of incident angles. And it can do all of this in the blue part of the visible spectrum, making it "the first negative index ...

and the result is an important step towards the creation of double-negative negative-index metamaterials (DN-NIMs) that operate in the visible range. Naturally occurring materials have a positive ...