‘Refueling aircraft with light’: Chinese laser tech could recharge drones mid-air

Researchers are developing a method to recharge drones mid-flight using laser beams directed at receivers placed beneath their wings. The team at the Civil Aviation University of China says the development addresses limited battery life, which is one of the biggest challenges in drone technology. The lightweight receiver has been designed to capture energy from a ground-based laser and convert it directly into electricity. Interestingly, the tech hinges on a perovskite laser cell-thermoelectric (PLC-TE) tandem device, a modified solar cell built to absorb high-powered laser beams rather than standard sunlight. “Imagine a future where drones inspecting forests, monitoring disasters, or delivering packages no longer need to land frequently to replace batteries,” said Jianhua Han, senior author from the Civil Aviation University of China. “Our work demonstrates the possibility of ‘refueling aircraft with light.’ Going from 1 to 100 will require solving many engineering challenges, but we hope this provides a starting point for future development,” the senior author added. Heat blocking challenge Beaming wireless power to drones long seemed impossible due to a physical obstacle: intense heat. Powerful lasers needed to generate flight-level electricity caused small receivers to overheat rapidly, destroying their efficiency and melting components before usable energy could be delivered. First, a dual-layer receiver comprising a perovskite laser cell coupled to a thermoelectric generator was designed. The top layer snaps up laser light and converts it into electricity, while the bottom layer harvests the waste heat to extract even more energy. During high-power laser testing, thermal cameras revealed unexpected temperatures reaching 80–90°C (176–194°F). To solve this, researchers embedded heat-blocking nanocrystals into the device to act as a thermal barrier. Then came the interesting part: aerodynamic integration. Rather than sticking a bulky sensor on top of the drone, the team tucked the ultra-thin receiver underneath the wing and carved customized air channels straight through the frame. As the drone flies, the rushing wind sweeps through the wing, naturally cooling the receiver’s back. The colder the back gets relative to the laser-scorched front, the more power the thermoelectric layer pumps out. “Previous studies largely focused on the materials or the device itself,” said 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.” Energy conversion efficiency In laboratory tests using a green laser beam, the system converted 38.49% of incoming laser energy into usable electricity. In a stationary proof-of-concept, the beam powered up a model propeller blade. It is a massive proof of concept, but big questions remain before sky-beaming becomes a commercial reality. The researchers still need to test the tech on an active, free-flying aircraft in unpredictable outdoor conditions. Apart from the power receiver itself, engineers must build rapid tracking optics that can lock onto a moving target miles in the air. All while ensuring a high-power green laser beam doesn’t accidentally blind a commercial pilot or slice through power lines. Still, the foundation is set. If we can charge our phones through nightstand pads, the sky shouldn’t be off-limits. With a little engineering flair and a lot of light, the era of perpetual flight might finally be on the horizon.The study was reported in the journal Matter & Light on July 29. Recommended ArticlesGet the latest in engineering, tech, space & science - delivered daily to your inbox.Mrigakshi is a science journalist who enjoys writing about space exploration, biology, and technological innovations. Her work has been featured in well-known publications including Nature India, Supercluster, The Weather Channel and Astronomy magazine. If you have pitches in mind, please do not hesitate to email her.