Refractory broadband absorber from visible to near infrared

Abstract:

We propose a refractory broadband absorber in hexagonally arrayed TiN-SiO2-TiN metamaterial. Through manipulating optical modes and their coupling, we obtain broadband absorber with absorptivity over 80% in visible to NIR. The flat absorption band forms with surface lattice resonance as low wavelength band edge, vertical gap plasmons as upper wavelength band edge, and the horizontal gap plasmons leverage the middle of the band. The intrinsic loss of TiN film at the bottom layer also provides great contribution of high absorption in short wave-length. Besides, the use of refractory material allows absorber to work in hard environment such as high tempera-ture, strong erodible and high-power laser incidence, etc. All these properties would make the refractory broadband absorber have potential usage in diversity optical devices.

Key words:metamaterial, broadband, perfect absorber, refractory material,