A new discovery will make it possible to create pixels just a few hundred nanometers across. The "nano-pixels" could pave the way for extremely high-resolution and low-energy thin, flexible displays for applications such as 'smart' glasses, synthetic retinas, and foldable screens.

Oxford University scientists explored the link between the electrical and optical properties of phase change materials (materials that can change from an amorphous to a crystalline state). By sandwiching a seven=nanometer-thick layer of a phase change material (GST) between two layers of a transparent electrode, the team found that they could use a tiny current to 'draw' images within the sandwich "stack."

Initially still images were created using an atomic force microscope, but the researchers went on to demonstrate that such tiny "stacks" can be turned into prototype pixel-like devices. These 'nano-pixels' – just 300 by 300 nanometers in size – can be electrically switched 'on and off' at will, creating the colored dots that would form the building blocks of an extremely high-resolution display technology.

Source 

Also: Learn about Slot-Sampled Optical PPM Demodulation.