Tunable metamaterials using a topological insulator at near-infrared regime

We present an effective method for actively controlling the intrinsic resonances of optical metamaterials in the near-infrared (NIR) spectral region using topological insulator (bismuth selenide, Bi2Se3) materials. The potential of Bi2Se3 as a dielectric interlayer of multilayer metamaterials (MMs) is explored. The optical response of elliptical nanohole arrays penetrating through metal/TI/metal (Au/Bi2Se3/Au) films is numerically investigated using the Finite Difference Time Domain (FDTD) method in the NIR region. The influence of increasing the immersion time of Bi2Se3 in a AgNO3 solution on the effective optical parameters of the structure is analyzed. This result suggests that a continuous wavelength shift of a structure's effective optical parameters can be obtained by modifying the immersion time.