Optical properties of tunable metallic nano-tubes by using an interband transition

The optical properties of a tunable metal-coated nano polymer are described in this study. The optical properties of metal-coated nano-polymer tubes are calculated by using a Finite-Difference Time-Domain (FDTD) method. To calculate the metallic part in the tube, we used Drude's model with the FDTD method. To obtain the optical properties, we also applied the optical theorem to the FDTD method. The optical properties of metals come from their optical constants and plasmonic structure. We calculate two kinds of metals, nickel and silver, to show the tunable optical properties. Also, we analyze the tubes by changing the thickness of the metal coating. We verify tunable optical properties for silver by using an interband transition.