Researchers have devised a method for printing full-color images at an unprecedented resolution. This ultra-high-definition printing method uses tiny rods (measured in the tens of nanometers) to manipulate light at the smallest scales, resulting in the highest resolution images allowed by physics.
Every pixel in the method is made from four tiny nanoscale posts topped with silver and gold. The research team based at Singapore's Agency for Science, Technology and Research (or A*STAR) have devised a method to manipulate what spectrum of light is reflected by altering the height of these posts and the distances between them. This effect is known as plasmon resonance, in which light at the tiniest of distances causes electrons in metal nanostructures to vibrate just so, thus determining the color reflected.
As it turns out, there is indeed a limit to how high a resolution an image can be. It's around 100,000 dpi, which you can compare to the top laser printers that peak at a mere 10,000 dpi. This process matches that limit. Even under the most advanced optical microscopes, when the distance between any two structures are less than half the wavelength of the light they are reflecting, a blurred-out refraction occurs. Wavelengths in the middle of the visual color spectrum are 500 nanometers, meaning that the highest clear image would have to place pixels at 250 nm apart, which this system does.
Put simply: the team has created the highest possible resolution printed image allowed by the known laws of physics.
In order to demonstrate the method's effectiveness, the team printed up a 50-by-50-micrometer version of "Lenna," the cropped image of a 1972 Playboy centerfold that has become the standard test image for research into compression and denoising in scientific publications. See below (it's perfectly SFW, BTW).
So, what's do these ultra-resolution images look like to the human eye? Northwestern University chemist Teri Odom told Scientific American that a human with perfect vision is not able to discern objects smaller than 20 micrometers, but still, any image printed in this method would appear "higher than high definition."
But producing ultra-resolution images may not be the ultimate goal of this technology. The team says the next step will be to devise a method for printing over larger scales. This technology could the be used to encrypt information at the teeny-tiniest scales, or act as physical optical storage like a DVD.