By Matt ReynoldsThey might not look like much but these miniature masterpieces are the width of a human hair. And despite their size, each packs in more pixels per square centimetre than the highest resolution screens available today.This level of detail is all down to a laser printing technique developed by Anders Kristensen and his team at the Technical University of Denmark in Copenhagen. By blasting lasers at a material made up of thousands of nanoscale plastic pillars covered with a thin layer of the element germanium, Kristensen has printed some of the highest resolution images ever made.The laser heats up each pillar to over 1000°C for a few nanoseconds, causing the germanium layer on its tip to change shape – which changes the colour of light it reflects and thus what colour it appears. Low intensity laser blasts cause it to reflect blue light, while ramping up the intensity shifts the colour towards reds and yellows. In this way, the surface of the material can be tuned so that each pillar reflects a different colour, ultimately allowing different images to be printed.The pillars are only a few tens of nanometres apart, which lets the team cram tens of thousands of spots of colour across every centimetre of the surface. The images above are just 50 nanometres wide and were printed at a resolution of 127,000 DPI (dots per inch). The display on an iPhone 7, for comparison, is 326 DPI.
Lasers print ultra high-res images narrower than a human hair