Additive Manufacturing of a 3D Terahertz Gradient‐Refractive Index Lens

A 3D terahertz gradient-refractive index lens designed by transformation optics is achieved by fabricating “woodpile” structures with varying dimensions of subwavelength dielectric unit cells using the projection microstereolithography technique. Both simulation and experimental investigations confirm that the lens delivers an imaging resolution very close to the diffraction limit over a frequency range from 0.4 to 0.6 THz.