Fabrication of terahertz holograms

The authors demonstrate the fabrication of polypropylene eight-level holograms with arbitrary patterns for use in terahertz beam forming and imaging applications. They make a binary master in silicon using multistage deep reactive ion etching. The pattern is then transferred into polypropylene using an imprint technique to make the final hologram. Patterns are tested using a 2 THz quantum cascade laser. The results show that the desired image is formed with the inclusion of a zero order mode. The process is low cost and with high fidelity. The demonstration of holograms in low loss material opens a new field of opportunity for those working on terahertz applications.