Printing at over 125000 dots per inch or 400 times the resolution of an iPhone 7 display

A new printing process can print images at 100,000 dpi, suggesting much higher resolution than can be obtained using pigmenting.

Some test images were 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.

Science Advances – Resonant laser printing of structural colors on high-index dielectric metasurfaces

Man-made structural colors, which originate from resonant interactions between visible light and manufactured nanostructures, are emerging as a solution for ink-free color printing. We show that non-iridescent structural colors can be conveniently produced by nanostructures made from high-index dielectric materials. Compared to plasmonic analogs, color surfaces with high-index dielectrics, such as germanium (Ge), have a lower reflectance, yielding a superior color contrast. Taking advantage of band-to-band absorption in Ge, we laser-postprocess Ge color metasurfaces with morphology-dependent resonances. Strong on-resonance energy absorption under pulsed laser irradiation locally elevates the lattice temperature (exceeding 1200 K) in an ultrashort time scale (1 ns). This forms the basis for resonant laser printing, where rapid melting allows for surface energy–driven morphology changes with associated modification of color appearance. Laser-printable high-index dielectric color metasurfaces are scalable to a large area and open a new paradigm for printing and decoration with nonfading and vibrant colors.