Negative-index metamaterial at 780 nm wavelength
  We further miniaturize a recently established silver-based negative-index metamaterial design. By comparing transmittance, reflectance and phase-sensitive time-of-flight experiments to theory, we infer a real part of the refractive index of -0.6 at 780 nm wavelength -- which is visible in the laboratory. 
Gunnar Dolling, Martin Wegener, Costas M. Soukoulis, Stefan Linden