An ultrathin and dual band metamaterial perfect absorber based on ZnSe for the polarization-independent in terahertz range

In this work, a new metamaterial design is proposed to yield an ultra-thin and dual band metamaterials perfect absorber (MPA) to be operated in the frequency range from 15 to 35 THz. The proposed structure is consisted of a copper resonator deposited on a very thin Zinc Selenide ZnSe (0.6 μm) substrate, where the backside of the structure is covered with a metal plate to block the transmission of electromagnetic waves. Computer Simulation Technology (CST) was used to design and investigate the proposed structure. The absorption response of the proposed structure was found to be high enough with absorptivity of 98.44 and 99.28 at 22.46 THz and 28.95 THz, respectively. Results showed that the absorber is insensitive to the incident angle of 0°–60° in both transverse electric (TE) and transverse magnetic (TM) modes, respectively. The MPA was seen to be highly independent on the angles of polarization of the incident waves. The working mechanism of the proposed design was revealed by multiple reflection interference theory and a good agreement was confirmed between the calculated and simulated results. The proposed design can be used for possible applications of stealth technology and imaging.