Optical transparency by detuned electrical dipoles

We demonstrate that optical transparency can be realized with plasmonic metamaterials using unit cells consisting of detuned electrical dipoles (DED), thereby mimicking the dressed-state picture of the electromagnetically induced transparency (EIT) in atomic physics. Theoretically analyzing the DED cells with two and three different silver ellipsoids, we show the possibility of reaching a ≥10 times decrease in group velocity and a propagation loss of ≤1 dB per cell within the optical wavelength range of 625–640 nm. Similar configurations are realized with lithographically fabricated gold nanorods placed on a glass substrate and subsequently covered with a ~15-μm-thick polymer layer, featuring EIT-like transmission spectra with transparency windows at wavelengths of ~850 nm.