Microtopography-Guided Chessboard-like Structure for a Broadband Terahertz Absorber

Broadband absorber in the terahertz frequency is highly required for applications in imaging, detecting, and electromagnetic stealth. The limitations for developing the absorber are not only the complex geometric structure and multimaterials themselves but also the time-consuming, expensive, and inaccurate manufacturing. Herein, a chessboard-like structure with an alternate distribution of Ti and Si materials in the plane is proposed. This quite simple microscale structure exhibits a large absorption in the terahertz range, which can work as an efficient broadband absorber. To fabricate the absorber, we have proposed a microtopographic substrate-guided method which possesses low-cost and high accuracy capacities. Finally, the proposed absorber exhibits above 60% absorption in 0.1-4 THz, while larger than 75% absorption is achieved in 2.1-4 THz. The similarity of the experimental and simulated absorption is up to 92%. These performances could fulfill the requirements for the applications in electromagnetic stealth, terahertz imaging, and sensing in the future. It also indicates that the proposed fabrication method can be effectively applied in preparing terahertz microstructures and metamaterials.