3D-printed terahertz metamaterial absorber based on vertical split-ring resonator

Terahertz metamaterials have received significant attention for their unprecedented abilities to modulate the terahertz wave effectively. The traditional manufacturing of terahertz metamaterials has been mainly relying on the micro-nanofabrication technique due to the micro-scale characteristic size of the unit cell. However, the fabrication usually involves multi-step and time-consuming processes, as well as expensive equipment. To overcome these shortcomings, here we used projection micro-stereolithography 3D printing followed by the magnetron sputtering to additively manufacture terahertz metamaterials. A vertical split-ring resonator-based metamaterial absorber is taken into account as the prototype to demonstrate the simplicity of the proposed fabrication technique. Both terahertz time-domain spectroscopy measurement and simulation indicate that the 3D printed absorber has a near-unity narrow-band absorption peak at 0.8 THz. The absorption mechanism is clearly clarified by the coupled mode and impedance matching theory and electromagnetic field distribution at the resonant frequency. A 3D printed narrow-band absorber also demonstrates great potential for highly efficient biosensing of lactose and galactose. It can be estimated that 3D printing provides an easy-going fabrication approach for THz metamaterials and shed light on its foreseeable application for the versatile design and manufacturing of functional THz devices.