It's difficult to manage color when you get to the nanoscale, but researchers from King's College London have found a way to trap light on nanostructures. Based on the shape of the structure, they can capture a rainbow created on gold film that's 100 times smaller than a human hair. Unlike a real rainbow, then, researchers can manipulate the structure to control where the colors show up. Jean-Sebastien Bouillard, a co-author of the study, wrote this in a statement: "The effects demonstrated here will be important to provide 'colour' sensitivity in infrared imaging systems for security and product control. It will also enable the construction of microscale spectrometers for sensing applications."