Energy from a laser beam could be used to power drones wirelessly, tests on new technology suggest.
While wireless charging for phones, watches and other tech has become commonplace, drones have needed to land to be powered up.
Now, researchers want to bring charging on the go to the skies by beaming a laser to receivers under the drones.
The solar-cell design would capture the energy and turn it into electricity, they report in the Cell Press journal, Matter & Light. The technology relies on a device optimised for lasers rather than sunlight.
Researchers said their tests demonstrated the possibility of refuelling aircraft with light but would require solving many engineering challenges before it became operational.
To keep the device cool, the researchers strategically placed it on the wings of a drone and utilised heat-blocking technology, allowing the receiver to convert more of the laser’s energy into usable power.
“Imagine a future where drones inspecting forests, monitoring disasters, or delivering packages no longer need to land frequently to replace batteries,” said senior author Jianhua Han, of the Civil Aviation University of China. “As drones take on longer missions, battery life has become one of the biggest barriers.”
Drones have also become a crucial tool on the battlefield, transforming the weaponry and tactics in Ukraine-Russia war and used frequently in the Iran war.
In the new project, a layer of perovskite, a type of calcium mineral, converts the energy into electricity, while a thermoelectric layer captures energy that would otherwise be lost as heat.
The greater the temperature difference between the warmer, laser-facing side and the other, cooler side, the more electricity the thermoelectric layer can generate.
But powerful lasers also heat the device significantly, eroding its efficiency.
“When we tested the device under a high-power laser, the thermal camera showed temperatures of 80°C to 90°C,” said Mr Han. “That was much higher than we expected and made us realise that heat build-up was a far more serious problem than we had imagined.”
To keep the device from cooking itself, the researchers embedded specialised nanocrystals into the device to act as a thermal barrier, slowing the flow of heat and helping the device maintain its performance.
Under a green laser, the static test system converted 38.49 per cent of the incoming energy into electricity, enough to power its propeller blade and keep one side cool.
“Previous studies largely focused on the materials or the device itself,” said Mr Han. “We wanted to think beyond the laboratory, to how the system could actually be integrated into an aircraft, cooled during operation, and made compatible with flight. It isn’t just a materials science problem – it’s an engineering one.”
The device has yet to take flight. Its next test will be on board a lightweight drone to prove that it can perform reliably outdoors. Researchers said they will also need to think about how to accurately track moving drones with laser beams and how to ensure the safety of the technology.
