Computer Generated Holograms using OAM beams: high-security optical elements for anti-counterfeiting applications

A computer-generated holograms (CGH) encoding information for light beams carrying orbital angular momentum (OAM) has been developed in collaboration between IOM-CNR and Padua University. The use of a numerical code, based on an iterative Fourier transform algorithm, allowed a phase-only diffractive optical element (PO-DOE) by exploiting a new method based on transmission through high-order spiral phase plates (SPPs). The phase pattern of the designed holographic DOEs has been fabricated using high-resolution Electron-Beam Lithography (EBL) and simple soft-lithographic replica moulding process. More detailed information at: https://www.nature.com/articles/s41598-017-18147-7 ( doi:10.1038/s41598-017-18147-7 ).