Chinese laser scientist ‘Crazy Li’ arms small drones with metal-cutting beam

A squad of fully armed soldiers follow closely behind a Humvee armoured vehicle, cautiously advancing through the ruins of an urban battlefield. About a kilometre ahead of them in the sky, a small drone hovers in place. Suddenly, one soldier lets out a scream, clutching his eyes with both hands as smoke curls between his fingers.

They have been hit by laser beams emitted by the drone. Near-infrared laser with a wavelength of 1080 nanometres can cause blindness at a power of just five microwatts. The beam intensity that enters these soldiers’ eyes is 200 million times that, reaching one kilowatt per square centimetre. If the exposed skin was hit, the subcutaneous fat would be instantly vaporised.

A laser of such an intensity is “sufficient to cut through metal”, wrote a research team led by Li Xiao, an associate researcher with the school of optoelectronic science and engineering of the National University of Defence Technology of the Chinese People’s Liberation Army, in a peer-reviewed paper published in the Chinese journal Acta Armamentarii in October.

Li’s email prefix – “crazy.li” – hints at his unconventional thinking. The scenario he envisioned in the paper was once deemed impossible: generating a laser beam with a long kill distance typically requires bulky equipment the size of a truck. A small platform, similar to a consumer drone, could never carry such a high-powered laser weapon and its accompanying energy supply equipment.

Li and his colleagues invented a small and lightweight redirecting device that allows drones equipped with it to receive powerful beams from the ground and reflect them onto enemy targets.