Terahertz metamaterial to demonstrate extremely wide range of effective refractive indices in the 0.3-THz band

Research on terahertz technology has progressed to offer game changing industrial applications. However, high-performance optical elements that manipulate electromagnetic waves in the terahertz waveband remain unrealized. Metamaterials can provide unprecedented refractive indices and offer a possible solution to the lack of optical elements. Here, we demonstrate simple control of parameters for identical kinds of meta-atoms allowing simple design of an extremely wide range of refractive indices including the high refractive index of 12.3, a refractive index near zero of -0.37, and a negative refractive index of -5.4 in the 0.3-THz band.