Loss compensated negative index material at optical wavelengths

We present a computational approach, allowing for a self-consistent treatment of three-dimensional (3D) fishnet metamaterial operating at 710 nm wavelength coupled to a gain material incorporated into the nanostructure. We show numerically that loss-free negative index material is achievable by incorporating gain material inside the fishnet structure. The effective gain coefficient of the combined fishnet-gain system is much larger than its bulk counterpart and the figure-of-merit (FOM = vertical bar Re(n)/Im(n)vertical bar) increases dramatically with gain. Transmission, reflection, and absorption data, as well as the retrieved effective parameters, are presented for the fishnet structure with and without gain. Published by Elsevier B.V.