Wireless charging power transmitted with lasers up to 100 feet away

A study on the wireless power transmission technology titled "Long-range wireless optical power transfer system using an EDFA" has been published in the journal Optics Express.

Researchers from Sejong University in South Korea have created a new laser charging system that can transmit power using infrared light over up to 30 meters (98.4 feet), offering a safe alternative to corded charging for mobile devices and powering the Internet of Things (IoT) devices spread throughout an area. The system could deliver 400 milliwatts (mW) of power across this distance, enough to charge sensors but not quite enough to charge mobile devices yet.

Wireless power transmission has been achieved over greater distances, but transmitting power safely across meter-scale distances has posed challenges. The researchers overcame this with a technique known as distributed laser charging, separating the laser's transmitter and receiver, creating a laser cavity between them through which light-based power can be transmitted. When a device interrupts the line of sight, the system automatically changes to a power-safe mode that allows it to deliver power wirelessly and safely.

"While most other approaches require the receiving device to be in a special charging cradle or to be stationary, distributed laser charging enables self-alignment without tracking processes as long as the transmitter and receiver are in the line of sight of each other. It also automatically shifts to a safe low power delivery mode if an object or a person blocks the line of sight," said research team leader Jinyong Ha.

"The ability to power devices wirelessly could eliminate the need to carry around power cables for our phones or tablets ... Using the laser charging system to replace power cords in factories could save on maintenance and replacement costs. This could be particularly useful in harsh environments where electrical connections can cause interference or pose a fire hazard," said Ha.

You can read more from the study here.