An ultra-broadband terahertz absorber at high terahertz frequency

Broadband absorber at high terahertz frequency is highly required for applications in imaging, detecting, electromagnetic stealth. Although intensive investigations of the broadband absorber have been taken, the challenges still exist both in design and fabrication of an ultra-broadband absorber at high frequency. Herein, a three-layered structure metamaterial has been designed to realize an ultra-broadband terahertz absorber covering 3.94-9.98 THz (6.04 THZ) at the absorption above 80%, and the absorption bandwidth can be increased to 7.64THz (2.34-9.98 THz) by rotating the absorber. Upon on the simulations, the proposed absorber exhibits insensitive to the TM and TE polarization, it means the absorption effect is almost consistent in different polarization modes, the proposed absorber is significant in the practical application. Nevertheless, the absorption bandwidth reduces a little bit to 5.05 THz (absorption > 60%) as beta increases to 45 degrees.