Creating Dichroic Paint
The Lycurgus cup is an example of nano technology. The glass it is made of is known as dichroic. A dichroic material is either one in which causes visible light to be split up into distinct beams of different wavelengths or one in which light rays having different polarizations are are absorbed by different amounts. The opaque green cup turns to a translucent red when light is shone through it. The glass contains tiny amounts of colloidal gold and silver. These nano sized particles give it these optical properties.
In my research in So Jung Park's lab at University of Pennsylvania, I created a paint made of Elmer's Glue (Poly vinyl alcohol) and gold nano particles that has these dichroic properties.