To a Sky Without Battery Drain: How Laser-Powered Drones are Transforming Logistics, Disaster Response, and Security

The performance of drones is rapidly evolving. High-resolution cameras, infrared sensors, autonomous flight powered by artificial intelligence, and high-precision surveying capabilities. As the capabilities that can be equipped increase, there is one weakness that has remained largely unchanged for years: the battery.

Small multicopters often have flight times limited to several tens of minutes. For long-term monitoring or surveying, multiple drones must be alternated, or operations must be interrupted to replace batteries. This constraint is particularly burdensome in locations where uninterrupted observation is required, such as disaster sites, forests, at sea, borders, and critical facilities.

Research in China is underway to overcome this limitation with light. A research team from the Civil Aviation University of China and Tsinghua University has developed a power reception system that converts laser light emitted from the ground into electricity on the drone side to power the propellers.

The announced photoelectric conversion efficiency is 38.49%. Looking at the numbers alone, one might imagine a future where drones can continue flying without landing by continuously receiving energy from the ground. However, this achievement is not the "completion of perpetual flight." It is necessary to separate the demonstrated scope from the challenges that need to be addressed in the future.

Converting Laser to Power Under the Wings

The device developed by the research team features a structure combining a perovskite-type cell that receives laser light and a thermoelectric conversion element that converts heat into electricity.

The mechanism is similar to solar power generation. A laser is emitted from a ground-based transmission device, and the light-receiving cell installed under the wing converts the light energy into direct current electricity. This electricity is used to drive the motors or reduce the consumption of the onboard battery.

In laser power transmission, energy is concentrated at specific wavelengths. Unlike sunlight, which includes various wavelengths, it is easier to design the light-receiving material to match the transmission laser. Perovskite materials can have their absorption characteristics altered by adjusting their composition, making it easy to create thin and lightweight devices. This can be a significant advantage for drones, where weight directly impacts flight performance.

In tests using green lasers, the power reception device converted 38.49% of the incident light energy into electricity. However, this value does not mean that 38.49% of the power received from the outlet by the transmission equipment reached the drone.

In an actual system, losses occur at multiple stages, including conversion from electricity to laser light, beam formation by optical devices, transmission through the atmosphere, and reconversion on the drone side. To evaluate practicality, the overall efficiency from the power source to the drone's motor is crucial.

The "Heat" Problem Arising from Increased Output

Increasing the laser's strength increases the power that can be received. However, not all of the received energy is converted into electricity. Much of the unconverted portion turns into heat.

In early tests, the temperature of the power reception device reportedly reached 80–90 degrees Celsius. As the temperature rises, conversion efficiency decreases, and it can lead to material degradation, damage to adhesive parts, and adverse effects on the drone's structure. If heat is transferred to the battery, safety risks also increase.

On ground equipment, large fans or heavy heat sinks can be added. However, on aircraft, increasing cooling equipment increases weight and air resistance, thus requiring more power for flight.

The research team controlled heat transfer by placing antimony selenide nanocrystals between the perovskite layer and the electrode. Additionally, they adopted a structure that guides the airflow generated by the propeller into the wing to cool the power reception device.

This ingenuity is crucial for understanding the value of the research. They are not only creating high-efficiency cells in the laboratory but also attempting to simultaneously address heat, weight, aerodynamics, and cooling when integrated into actual aircraft.

Demonstration at the Model Stage, Not "Flying Drones"

From the headline "Charging Drones in Flight with Lasers," some might imagine tests where beams were continuously aimed at drones flying outdoors.

However, according to the disclosed research information, at this stage, it is a proof of concept where a power reception device was installed under the wing of a stationary drone model, and the propeller was driven by the irradiated laser. It is not at the stage of tracking and flying an actual lightweight drone outdoors for extended periods.

This difference is not insignificant.

With a fixed model, it is relatively easy to keep the laser focused on the light-receiving surface. An actual aircraft sways in the wind, turns, and changes speed and altitude. The angle of the wings also changes. If the beam strays from the light-receiving surface, the supplied power could drop sharply.

On the transmission side, technology is needed to grasp the position and posture of the aircraft in real-time and predict the direction of travel while keeping the laser in pursuit. It will likely involve a combination of cameras, infrared sensors, radar, and position information sent from the aircraft.

Widening the beam makes it easier to hit the target, but the energy disperses. Narrowing it allows for high-density power transmission, but it increases the demands on tracking accuracy and safety. This challenging balance is a major barrier to practical application.

The research team also considers precise real-time tracking a future challenge and plans outdoor tests using lightweight actual aircraft in the next phase.

Rain, Fog, Smoke—Weaknesses Because It's Light

Laser power transmission requires a line of sight between the transmission and reception devices. If obstructed by buildings, trees, or terrain, power cannot be transmitted.

Moreover, rain, fog, clouds, dust, and smoke from fires scatter and absorb light, reducing the energy that reaches the target. Related research has also analyzed that when atmospheric turbulence becomes moderate to strong, the performance of communication networks using laser-powered drones clearly declines.

This is an ironic issue. At disaster sites where laser power transmission is expected, heavy rain, smoke, and dust are likely to occur. In forest monitoring, trees become obstacles, and in urban areas, tall buildings and other aircraft might enter the beam path.

Therefore, a practical system might not cover a wide area with a single laser device but rather deploy multiple power transmission bases and switch the transmission source according to the drone's movement. The concept is to create an invisible "charging corridor" in the sky, allowing drones to continue their missions within that range.

Even Without Complete Infinite Flight, There Is Value

Even if a drone cannot fly perpetually with just lasers, there is significant value if it can reduce battery consumption and extend flight time several times over.

In disaster response, it can continuously transmit images of the affected area, search for missing persons, and relay communications. In wildfires, it can observe the direction of spread and wind direction for extended periods. It can also serve as a temporary communication base station in areas where roads have been cut off by floods or earthquakes.

In agriculture, it can continuously monitor the growth conditions and diseases of large farmlands. In infrastructure inspection, it can patrol power lines, railways, pipelines, bridges, and maritime facilities for extended periods. It can also be used to monitor the direction of travel and surroundings by flying continuously over ships, trains, and security vehicles.

In logistics, drones that fly back and forth on predetermined routes might be realized sooner than delivery machines that can fly freely anywhere. If they fly between bases equipped with power transmission facilities and supplement power along the way, it becomes easier to limit the tracking range and safety zones.

The U.S. Also Advances the "Power Transmission Network of Light"

Laser power transmission is not a research theme exclusive to China.

The U.S. Defense Advanced Research Projects Agency's (DARPA) POWER program transmitted over 800 watts of power to a reception device 8.6 kilometers away for 30 seconds in 2025, transmitting over 1 megajoule throughout the test period. Although the test was conducted between ground facilities, it was an achievement that demonstrated the potential of long-distance optical power transmission.

U.S. company PowerLight Technologies is also developing a system to transmit kilowatt-class power while tracking a moving fixed-wing drone. In 2026, it was reported that they flew a military-class fixed-wing drone for several hours in a test related to the U.S. Department of Defense.

The recent achievement in China is characterized by integrating perovskite light-receiving cells with thermoelectric conversion, enhancing the efficiency and cooling of lightweight power reception devices. On the other hand, U.S. developments focus on integrated systems, including long-distance transmission, mobile tracking, safety control, and communication with the aircraft.

Even with the same laser power transmission, the competition is not merely a comparison of conversion efficiencies. It is a competition of comprehensive technologies, including materials, optics, tracking control, aircraft design, and energy network operation.

The Greatest Demand May Be in the Military Sector

One of the sectors that most needs drones capable of long-term flight is the military and security sector.

If reconnaissance aircraft can fly for extended periods, they can continuously monitor the movements of troops and vehicles. Maintaining communication relays at high altitudes can expand the communication range of ground forces. They can also be used for vigilance around borders, coasts, and bases.

However, while laser power transmission frees the aircraft, it creates dependency on ground power transmission equipment. Bases equipped with large power sources and precise optical devices may be discovered and attacked, and the range of use may be limited by weather and terrain. If the position of the laser is detected by optical sensors, there is a risk that the power transmission base or flight route could be inferred.

Nevertheless, there is strong demand for applications that keep surveillance aircraft and communication relays airborne around forward bases, ships, and fixed facilities. This is why there is a view that military use might precede civilian use.

Reactions on Social Media—Not Just "Amazing"

On public social media and technical forums, there is notable surprise at laser power transmission itself. Reactions include evaluations of technological progress, such as "I didn't think wireless power transmission had advanced this far" and "It's like science fiction."

As for applications, disaster monitoring, regular observation of farmland, advance monitoring of ships and trains, and temporary communication base stations are mentioned. Particularly for drones that remain at a certain point or within a narrow range, there are many opinions that it is more realistic than delivery machines with a wide range of movement.

On the other hand, there are severe doubts about practicality.

The most common concerns are the weight and air resistance of the power reception device. Adding new equipment to the aircraft increases the power required for flight. If a larger aircraft is needed to carry the power reception device, the amount of power transmission must also be increased.

In terms of cost, there are suggestions like "Isn't it cheaper to prepare spare batteries or a second drone?" For operations where brief landings are allowed, automatic charging docks or battery replacement facilities are often simpler and safer.

There are also strong voices questioning safety. Concerns include the danger if the laser enters the eyes of people or animals, the function to stop if an aircraft or bird enters the beam path, and measures if the irradiation direction shifts due to malfunction or cyberattack.

Additionally, there are concerns like "Will it ultimately be used for constant surveillance or warfare?" If cameras that remain in the sky 24 hours a day are deployed in cities or borders, they could aid in disaster prevention and security maintenance, but there is also the possibility of surveillance becoming routine.

These are not statistically analyzed results of the entire SNS, but rather qualitative trends organized from related public posts and opinions on forums. Even so, it is clear that users are looking at not just the conversion efficiency numbers but also costs, weight, weather, safety, privacy, and military diversion simultaneously.

Safety Rules More Challenging Than Technology

Given that high-power lasers are directed into the sky, the establishment of safety regulations is essential.

The power transmission system needs a function to stop irradiation the moment a person, aircraft, bird, or vehicle enters the beam path. It must also automatically stop if the aircraft deviates from the designated airspace or if communication is lost.

Furthermore, it is necessary to anticipate cyber security attacks such as spoofing of location information, intrusion into tracking software, and impersonation of power reception devices. It is required to constantly verify not only that the laser does not deviate from the target but also that "the correct output is being sent to the correct aircraft in the authorized airspace."

To popularize it in urban areas, adjustments must be made to aviation laws, laser equipment safety standards, facility installation regulations, privacy protection, and responsibility sharing in the event of an accident. The fact that it is technically possible and that it can be operated in society are separate issues.

A More Realistic Future Than "Infinite Flight"

The realistic form of laser-powered drones is likely not an aircraft completely devoid of batteries.

Normally, they fly on batteries and receive power from lasers when entering designated airspace. In fair weather, they use optical power transmission; in bad weather, they use landing-based charging; and in emergencies, they use replacement batteries. For fixed-wing aircraft that also use solar cells, operation using sunlight during the day and ground lasers at night can also be considered.

In other words, lasers are likely to become a technology that extends mission time by combining multiple energy sources, rather than a magic solution for achieving perpetual flight on their own.

The achievement of the Chinese team this time is not the realization of infinite flight for actual aircraft. Nevertheless, the integration of a high-efficiency power reception device that converts light into electricity into aircraft and the suppression of the biggest problem, heat, from both material and airflow perspectives is a significant advancement.

The next focus is clear. How accurately can lightweight drones flying outdoors be tracked? How much power can be delivered in rain or fog? Are the overall efficiency and cost, including power transmission equipment, realistic? Can high-power lasers be brought to a safety standard acceptable to society?

The era of determining drone flight time solely by the amount of battery onboard is beginning to change. Machines flying in the sky receive light from the ground and convert that light into energy. What was once a science fiction concept has now become a real development competition crossing materials science, aeronautical engineering, optics, and legal systems.

Whether the term "infinite flight" becomes a reality depends more on solving the many challenges surrounding it than on the conversion efficiency figure of 38.49%.

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