Low-loss negative-index metamaterial at telecommunication wavelengths

Abstract

We fabricate and characterize a low-loss silver-based negative-index metamaterial based on the design of a recent theoretical proposal. Comparing the measured transmittance and reflectance spectra with theory reveals good agreement. We retrieve a real part of the refractive index of $\mathrm{Re}\left(n\right)=-2$ around $1.5\mu \mathrm{m}$ wavelength. The maximum of the ratio of the real to the imaginary part of the refractive index is about three at a spectral position where $\mathrm{Re}\left(n\right)=-1$. To the best of our knowledge, this is the best figure of merit reported for any negative-index photonic metamaterial to date.