Although your mobile phone might have a high-quality colour screen, it can’t display pictures in both the visible spectrum and other wavelengths of light at the same time. Now, researchers have engineered a device that can show images in wavelengths ranging from visible to microwave simultaneously.
A team led by Coskun Kocabas at the University of Manchester, UK, made a display by layering sheets of graphene — a conductive, carbon-based film — over a foil sheet that acts a source of lithium ions. When electricity flows through the material, lithium ions trickle from the foil into the graphene. As the graphene incorporates more lithium, the display reflects a broader range of wavelengths.
The researchers can target the flow of electricity to individual units in the display. This allows the device to generate three images at the same time, although only one can be seen with the naked eye. When the device is observed with infrared light, a second image appears alongside the first; a third image can be seen only by observing the display with wavelengths that lie between far infrared and microwave.
The authors suggest that after further development, the device could be used for message encryption and camouflage coating.