Researchers in Singapore have achieved what they claim is the “highest possible resolution” for color laser printing.
The printer, developed by researchers at the Agency for Science, Technology and Research (A*STAR) in Singapore, prints images at a staggering 100,000 dots per inch, in full color. To do that, each pixel in the ultra-resolution image is printed by depositing four nanoscale pillars just tens of nanometers tall, which are then capped with silver and gold nanodisks.
The team demonstrated the technique by printing the common Lena test image at just 50 by 50 micrometers and around 100,000dpi — any smaller and the light would bounce off each pixel and diffract, resulting in a blurry picture.
By varying the diameter and spacing of these microscopic structures, it’s possible to control what color of light they reflect—a concept known as structural color—to develop a palette that can be used for full-color printing. The technique is described in Nature Nanotechnology.
The new method boasts resolution ten times higher than the highest-res laser and inkjet printers. In fact, this image is at the limit of optical resolution: if the researchers put the pixels any closer together, light reflecting off them will diffract, and the two objects blur together. In other words, scientists currently believe that printing can never get higher-res than this.
There are other applications for such a dramatic leap in printed resolution: steganographers will no doubt be thrilled at the potential for sending hidden messages, and it could be used for optical data storage or lithographic etchings.
For a more detailed dive into the science behind the new technique, take a read of Nature’s long article on the subject.