Phys.org  March 18, 2024 Researchers in Austria produced a sub-terahertz holographic image of a two-dimensional 576-bit data code using a diffractive phase-plate element. The phase plate was designed to encode a focused image of the data code into a phase modulation profile. The complex phase plate structure is fabricated from polylactic acid using fused deposition modeling, a common three-dimensional-printing technique. The simplified optical setup, consisted of a 0.14 THz diverging source, the holographic phase plate, and a scanning detector, without the need for additional optical elements. The information stored in the data code was an example of a cryptographic private […]