China Develops Laser Tech That Can Read Tiny Text From Nearly 2km Away

Scientists in China say they have developed a laser that can observe tiny text and other fine details at a higher resolution from a distance of 1.36 kilometres. In a study published in the journal Physical Review Letters, researchers from the University of Science and Technology of China tested a new laser-based system that they say can pick up small details from nearly a mile away. The researchers took a new approach based on the way light hits a surface, rather than focusing on the image itself. This method is called active intensity interferometry. The Chinese scientists demonstrated that the method could be used to detect objects that, unlike stars, are not self-luminous. 

According to Science Alert, the researcher tested an instrument that emits eight infrared laser beams fired across a specific point in the distance. Two telescopes were then used to capture the intensity of the light reflections. Through a careful calibration of the eight laser beams lighting up the target, the image can be reconstructed by comparing variations between the readings from the two telescopes, researchers explained. 

"Through outdoor experiments, we have successfully imaged millimetre-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 wrote. 

The researchers believe this method is "promising for high-resolution optical imaging and sensing".

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The Chinese scientists revealed that through their setup, they were able to accurately read letters at a resolution of 3mm, smaller than the width of a pencil. That's a 14-fold improvement in spatial resolution compared to what a single telescope could achieve, they said. 

However, the researchers noted that there are still a few limitations they have to overcome - for example, it needs a clear line of sight to the object. The target must be illuminated with lasers, so it may not be suitable for surveillance scenarios where stealth is required.

The team said that they have plans to improve the control of the laser as well, so that they are easier to direct. Moreover, the researchers may install artificial intelligence (AI), which could help reconstruct images more accurately.