Slow light with electromagnetically induced transparency in metamaterials

This study demonstrates a metamaterial with two coupled split-ring resonators (SRR) can exhibit an effect reminiscent of electromagnetically induced transparency (EIT), a coherent process normally observed in three-level atomic media. The coupling between two SRR induces a frequency splitting in the spectral response of the metamaterial, opening up a narrow transmission band in the centre of the absorption line. The obtained reduction in group velocity together with the low absorption is useful for a variety of slow-light applications, without the need for the extreme cooling or the large magnetic fields that are typically required for EIT in atomic systems.