3D printing opens up an inexpensive, rapid, and versatile path to the fabrication of optical elements suited to the terahertz regime. The transmission of the plastics used in 3D printers, while generally decreasing with frequency, is usable over the range 0.1-2 THz. We have designed, fabricated, and tested regular and blazed gratings and aspherical lenses for operation at terahertz frequencies. We find that the measured performance matches our theoretical predictions.
Squires, A. D., Constable, E. & Lewis, R. A. (2015). 3D printed terahertz diffraction gratings and lenses. Journal of Infrared, Millimeter, and Terahertz Waves, 36 (1), 72-80.