Abstract-A broadband terahertz absorber using multi-layer stacked bars

Shuo Liu¹, Haibing Chen¹ and Tie Jun Cui^1,2,a)
 http://scitation.aip.org/content/aip/journal/apl/106/15/10.1063/1.4918289
1 State Key Laboratory of Millimeter Waves, Department of Radio Engineering, Southeast University, Nanjing 210096, China
2 Cooperative Innovation Centre of Terahertz Science, No. 4, Section 2, North Jianshe Road, Chengdu 610054, China
a) tjcui@seu.edu.cn
Appl. Phys. Lett. 106, 151601 (2015); http://dx.doi.org/10.1063/1.4918289

We present the simulation, implementation, and measurement of a broadband terahertz (THz) metamaterial absorber. By stacking 12 metallic bars of varying lengths on three polyimide layers with equal spacing, a broadband absorption spectrum is formed through merging multiple successive resonance peaks. The measured total absorption exceeds 95% from 0.81 to 1.32 THz at the normal incidence and the full width at half maximum is 64% (from 0.76 to 1.48 THz). The absorption decreases with fluctuations as the incident angle increases but remains above 62% even at the incident angle of 40°. The physical explanation to the absorption mechanism is presented and verified by a 9-bar example, which exhibits narrower absorption bandwidth. It is also experimentally demonstrated that the proposed structure is robust against misalignment of each metallic layer.