3D-Printed All-Resin Terahertz Phase-Gradient Metamaterials for Multiple Wavefront Manipulations

Terahertz (THz) metamaterials, capable of manipulating the incident waves, are experiencing an unprecedented developing opportunity for THz science and applications. The high-efficient fabrication technique of THz metamaterials is indeed important for the widespread THz applications in the future. Here, we utilize 3D-printing technique to fabricate all-resin THz metamaterials for arbitrary control of THz wavefront. The unit phases of the conventional metasurfaces are uncertainly correlated with the in-plane geometries, herein the propagation phases of the designed units are linearly controlled by varying the thickness of the resin bricks. Then, the rectangular pillars are designed to place on the bricks to construct units and their geometric phases are manipulated by varying the orientations of the pillars. By superposing the above propagation and geometric phases, a spin-multiplexing principle is proposed to construct the non-interleaved multiplexed holography and focusing. The 3D-printing-assisted fabrication approach allows a flexible and efficient customization of phase-gradient THz metamaterials and may inspire versatile potentials in resonance-based THz sensing, imaging and information encryption.