Masked Stereolithography 3D-printed Terahertz Diffractive Lens

The design, fabrication, characterization of a 3D-printed terahertz diffractive lens operating at 300 GHz is presented. The designed diffraction lens is composed of connected rectangular pillars to enhance mechanical stability. The size of the square pixel is $500 \mu \mathrm{m}$, and the height of the prisms changed from $200 \mu \mathrm{m}$ to $1800 \mu \mathrm{m}$ to fully control $2 \pi$ phase, based on the meta-atom library. Moreover, we use a commercial masked stereolithography (MSLA) 3D printer to fabricate the diffraction lens rapidly with precise structural accuracy and low cost. Here, we demonstrate that the terahertz focusing ability of 3D printed diffraction lens and the new possibility of functional flat THz optics through additive manufacturing techniques.