We’re all familiar with the 2-D holograms and fluorescent codes used to guard against fakery in everything from credit cards to passports to currency. A team of engineers from Germany has put on the table a method that would literally take those optical security measures to another dimension. Specifically, the research team – from the Karlsruher Institute Für Technologie (KIT) and Carl Zeiss AG – has demonstrated a technique that uses laser nanoprinting to create tiny, 3-D fluorescent codes.