Three-Dimensional Printed Ultrabroadband Terahertz Metamaterial Absorbers

Terahertz (THz) absorbers have recently attracted extensive attention for their promising potential in various applications; however, many existing THz absorbers are restrained by their narrow bandwidth and complicated and costly fabrication process that renders them unfavorable for practical devices. Herein, we propose a stereoscopic multilayered ultrabroadband THz metamaterial absorber by stacking multilayer concentric resonators on different-level top surfaces of a monolithic three-dimensional (3D) pagodalike substrate. By taking full advantage of the 3D printing technique, the proposed ultrabroadband absorber can be produced efficiently in an easy three-step process that overcomes the fabrication complexities of traditional multistep photolithography processes. Additionally, the feasibility and robustness of the proposed fabrication method for common out-of-plane THz narrowband absorbers are also validated, and the absorption capacities of the 3D printed absorbers are numerically and experimentally elucidated. These results might provide an efficient concept and fabrication technique to stimulate many potential applications in emerging THz technologies, such as sensing, imaging, and wireless communications.