Visible plasmonic perfect absorber based on titanium nitride metamaterial

We theoretically calculated a metamaterial perfect absorber that exhibits broadband perfect absorption in the visible region using TiN nanostructures as resonator. We designed a 200 nm diameter TiN nanodisks array covered with a 5 nm thick TiO2 film. We used the FDTD method to obtain numerical values for reflectance, transmittance, and absorptance. By optimizing the structure design, we found that the average absorption with the TiN nanoresonators is 97% in the wavelength range from 350 nm to 750 nm. The calculated electric field distribution indicates a strong localized optical field around the TiN nanodisk which enhanced the light absorption.