The Laser-Powered Drone Has Not Flown Yet
A new receiver powered a stationary propeller efficiently, but flight, tracking, range and safety tests still lie ahead.
A new receiver powered a stationary propeller efficiently, but flight, tracking, range and safety tests still lie ahead.
Several headlines this week suggested that researchers had charged a drone in mid-flight with a laser. The experiment was interesting, but it did not do that.
A team from the Civil Aviation University of China and Tsinghua University built a receiver that converted green laser light into electricity at 38.49 percent efficiency. The device was mounted beneath the wing of a stationary drone model and powered its propeller. The aircraft did not fly, and the next planned step is an outdoor test on a lightweight drone.
That gap between the headline and the demonstration does not make the research trivial. It shows where progress has actually occurred. The team improved the receiver and its cooling, two difficult parts of sending useful power through the air. The harder system-level problems remain open.
The receiver combines two energy-conversion devices. Its first layer is a perovskite laser cell, a semiconductor device tuned to turn concentrated laser light into electricity. Perovskite here refers to the material’s crystal structure. The researchers used cesium lead bromide, which responds well to blue and green light.
The second layer is a thermoelectric generator. It produces electricity from a temperature difference. Instead of treating all the receiver’s heat as waste, the tandem design uses some of that heat as another source of electrical output.
Heat is also the design’s main obstacle. Under a high-power laser, the researchers measured temperatures between 80 and 90 degrees Celsius. That level of heating reduces photovoltaic performance and can accelerate material degradation.
The team added antimony triselenide nanocrystals to the perovskite layer. These particles slowed heat flow and improved the material’s charge transport. The researchers also placed air channels in the model wing, allowing airflow from the propeller to cool the thermoelectric layer’s cold side. A larger temperature difference helps that layer generate more power.
Under 520-nanometre green light at an incident power density of 1.2 watts per square centimetre, the combined receiver reached the reported 38.49 percent power-conversion efficiency. That is a meaningful laboratory result for the receiving device.
It is not the efficiency of a complete airborne power system. Electricity must first run a laser on the ground. The beam then travels through air, where pointing errors, distance, haze and turbulence can reduce the energy that reaches the aircraft. The receiver converts only the surviving light, after which motors and electronics consume the resulting electricity. The published percentage covers one section of that chain.
The proof of concept showed that the receiver could produce enough electricity to turn a propeller on a stationary model. It did not demonstrate a closed loop that tracks a moving aircraft, maintains beam alignment, charges a battery and supplies the changing power needed for stable flight.
Those distinctions matter because a drone does not draw constant power. Takeoff, climbing, gust compensation and manoeuvring can produce sharp changes in demand. A receiver must remain illuminated while the aircraft changes position and attitude. Added hardware must also earn back its weight through longer endurance.
Outdoor laser transmission introduces another constraint. A concentrated beam must stop or redirect safely if it loses the intended receiver. Clouds, dust and atmospheric distortion may alter its path or intensity. The researchers explicitly identify real-time tracking and safe outdoor operation as work still to be done.
Independent coverage from Professional Engineering and Hackster correctly describes the setup as a stationary model. Live Science also notes in its image caption and later reporting that a real in-flight demonstration is planned rather than completed, despite using a stronger headline.
Battery endurance limits inspections, mapping, emergency monitoring and other drone work. Supplying energy remotely could extend missions without carrying a much larger battery. Laser power is attractive because a focused beam can deliver energy farther than the magnetic coupling used by a phone charging pad.
The new research advances that possibility by addressing a receiver problem that worsens as laser power rises. The tandem device recovers some waste heat, while the nanocrystals and wing airflow manage temperature. It also treats aircraft integration as part of the design rather than an afterthought.
The honest conclusion is not that unlimited drone flight has arrived. It is that one receiver crossed a useful efficiency threshold on a bench and powered an aircraft component while managing high heat. A flying demonstration would be the next newsworthy step. Reliable tracking, end-to-end efficiency, weather tolerance and beam safety will determine whether the idea becomes an operational tool.