Active Tuning of Effective Refractive Index Based on Double-Layered Closed-Ring Resonator Array Terahertz Metamaterials

摘要

We numerically demonstrate index-tuning capability of terahertz (THz) metamaterials made of double-layered closed-ring resonator (CRR) arrays. The double-layered CRR arrays show narrow-band transmission peak in a relatively wide stop band and that peak show spectral shift by slightly shifting relative position of the CRR arrays or changing dielectric constant of the dielectric media inserted between CRR arrays. We also show that effective refractive index can be widely tuned by the same working principle from unnaturally high positive to near-zero and negative values. Our approach may open the way for the development of novel type of THz active devices.