3-D printed nanomaterial shows different transparencies and colours
(PHYSorg.com Nanotechnology)

Metallic nanoparticles have been used as glass colorants since the Roman Empire. One of the most famous pieces of pottery from the period is the Lycurgus cup. The nanoparticles embedded in this cup have an optical peculiarity, presenting different colours depending on the angle of the illumination. This effect is called dichroism. Now, scientists from Wageningen University & Research have made 3-D printed objects showing this dichroic effect.