Modulating the fundamental inductive-capacitive resonance in asymmetric double-split ring terahertz metamaterials

We investigate resonant transmission of planar asymmetric metamaterials made from double split-ring resonators. As the symmetry of the unit cell resonator is broken by displacing the two gaps away from the center in opposite directions, a giant amplitude modulation is observed at the fundamental inductive-capacitive resonance due to strong polarization conversion. The modulation is nearly absent when the gaps are moved together in the same direction. This effect persists in metamaterials with different structural designs. These asymmetric metamaterials may open up new avenues toward the control of terahertz waves and the development of modulator and polarizer based terahertz devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3571288]