The US military has just achieved a technological breakthrough in wireless power transmission. A laser carried over 800 watts across an impressive distance of 5.3 miles (8.6 kilometers).
The optical power transmission receiver designed for DARPA's experiment.
Credit: DARPA
This experiment, conducted by DARPA (the US military's research agency) as part of its POWER program, represents a major step toward instantaneous power transmission. It far surpasses previous program records, which had achieved 230 watts over 1.1 miles (1.7 kilometers) for 25 seconds.
The concept of wireless power transmission isn't new, dating back to Nikola Tesla's work in the early 20th century. However, technical obstacles have long delayed its development. Today, interest in this technology is resurging, particularly for military and space applications.
Energy is a critical element for military operations, and its transport to conflict or disaster zones is often unpredictable and risky. DARPA sees this technology as a potential solution for quickly and efficiently powering drones or other equipment in the field.
During this latest test, conducted at White Sands Missile Range in New Mexico, the laser was transmitted with approximately 20% efficiency. Some of the energy was used to pop popcorn in a highly visual demonstration.
Next steps for the POWER program include testing power transmission through multiple relays and at altitude, where the atmosphere is less dense and transmission more efficient.
How does laser-based wireless power transmission work?
Laser-based wireless power transmission relies on converting electricity into laser light, which is then directed to a receiver equipped with photovoltaic cells. These cells convert the light back into electricity, enabling remote powering of devices.
This technology offers the advantage of transporting energy over long distances without requiring cables, which is particularly useful in hazardous or inaccessible environments. However, conversion efficiency and atmospheric losses remain major obstacles.
Potential applications are vast, ranging from powering drones in flight to supplying energy in disaster zones. DARPA is also exploring its use for space projects, where the absence of atmosphere could significantly increase transmission efficiency.