Topological insulator metamaterials with tunable negative refractive index in the optical region

A blue-shift tunable metamaterial(MM) exhibiting a double-negative refractive index based on topological insulator (Bismuth Selenide, Bi 2 Se 3 ) has been demonstrated in the near-infrared(NIR) spectral region. The potential of Bi 2 Se 3 as a dielectric interlayer of the multilayer MM is explored. The optical response of elliptical nanohole arrays penetrating through Au/Bi 2 Se 3 /Au films is numerically investigated using the finite difference time domain (FDTD) method. The blue-shift tuning range of the MM is as high as 370nm (from 2140nm to 1770nm) after switching the Bi 2 Se 3 between its trigonal and orthorhombic states.