Polarization-independent dual narrow-band perfect metamaterial absorber for optical communication

In this paper, we demonstrate a dual narrow-band perfect metamaterial absorber for optical communication, where a silicon nano-disk array is placed on a thin gold film separated by a dielectric layer. Numerical results reveal that dual narrow-band perfect absorption peaks, which are attributed to waveguide mode and magnetic dipole resonance mode, are achieved at 1310 and 1550 nm, respectively. The results show that the absorption of the two peaks is higher than 99% under the normal incidence of both TE and TM polarizations and the bandwidth is 5 and 15 nm, respectively. Moreover, the absorption peak at 1310 nm can be independently tuned by varying the thickness of the dielectric layer. These findings imply that the proposed absorber can be used in the field of optical communication, frequency-selective photodetection, and intersatellite laser communication.