Superconductivity-Induced Transparency in Terahertz Metamaterials
A plasmonic analogue of electromagnetically induced transparancy is activated and tuned in the terahertz (THz) range in asymmetric metamaterials fabricated from high critical temperature (T-c) superconductor thin films. The asymmetric design provides a near-field coupling between a superradiant and a subradiant plasmonic mode, which has been widely tuned through super-conductivity and monitored by Fourier transform infrared spectroscopy. The sharp transparency window that appears in the extinction spectrum exhibits a relative modulation up to 50% activated by temperature change. The interplay between ohmic and radiative damping, which can be independently tuned and controlled, allows for engineering the electromagnetically induced transparency of the metamaterial far beyond the current state-of-the-art, which relies on standard metals or low-T-c superconductors.