The invisible hologram was developed by researchers at the Ulsan National Institute of Science and Technology in South Korea. Its reportedly simple manufacturing process and usage make it an attractive innovation. The hologram’s so-called SAPCs (self-assembled photonic crystals) can be individually manufactured with commercially available inkjet printers, and their authenticity can be verified without special equipment.
Because the special holograms are invisible on a white background in the light of day, they could even be used as hidden security labels. Additionally, no special equipment is required to inspect them: A strong source of light (such as a smartphone flashlight) and a dark background are sufficient for verification.
A further advantage: The holograms can be printed in various colours, lending them not only unique forms, but also a unique colouration. When inspected, the otherwise invisible hologram will then show the chosen colours or colour gradients, which can serve to provide another layer of visual encryption.