Low-loss negative-index metamaterial at telecommunication wavelengths

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 Re(n)=-2 around 1.5 mu 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 Re(n)=-1. To the best of our knowledge, this is the best figure of merit reported for any negative-index photonic metarnaterial to date. (c) 2006 Optical Society of America.