Scientists read millimeter-size text over kilometre away

What if you could read tiny text on a bottle more than a kilometre away—without any zoom lenses or high-powered cameras? Sounds like spy tech, but Chinese scientists have just made it real, using lasers and cutting-edge algorithms to bring distant details into sharp focus like never before.

They have developed a groundbreaking laser-based imaging system that can clearly detect tiny details, such as text just three millimetres tall, from as far as 1.36 kilometres (about 0.85 miles)—roughly the length of 14 football fields, according to a scientific website. 

This innovation holds promise for a range of applications, including enabling archaeologists to study ancient cliff carvings without climbing and helping environmental researchers monitor wildlife habitats from afar.

Traditionally, observing fine details at long distances has been hindered by atmospheric distortion, which blurs and scatters light, making it difficult for telescopes or lenses to capture small features like printed text. The new technique overcomes these obstacles by focusing not on forming a traditional image but on analyzing how light behaves when it reflects off a surface. Known as active intensity interferometry, the method uses eight infrared laser beams aimed at a target, with the reflected light collected by two telescopes spaced apart.

Rather than capturing static images, the telescopes detect subtle shifts in light intensity, which computer algorithms then process to reconstruct detailed surface features. The researchers noted that standard telescopes at this distance can only resolve objects about 42 millimeters in size, too large to read small text.

“Through outdoor experiments, we have successfully imaged millimeter-scale targets located at 1.36 km away, achieving a resolution enhancement by about 14 times over the diffraction limit of a single telescope,” the study authors explained.

While promising, the technology currently requires precise alignment of lasers and telescopes and an unobstructed line of sight with the target illuminated by lasers, limiting its use in stealth scenarios. The research team is now working on improving laser control and using AI-driven algorithms to further enhance image reconstruction accuracy, paving the way for broader applications in the future.

By Naila Huseynova