Broadband and efficient terahertz beam scanning using a 3D-printed Risley prism

We present a Risley prism beam-scanning system for terahertz waves. The scanning system consists of two 3Dprinted prisms made of cyclic olefin copolymer (COC), which is a low loss material at terahertz frequencies. The two prisms are mounted in a custom-fabricated, motorised holder to rotate the two prisms independently with high precision. A maximum beam deflection angle of 10.5 ° is demonstrated experimentally over a frequency range of 220 GHz to 330 GHz, with an average transmission efficiency of 81.5%.