October 1, 2022
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Infrared laser wireless power system delivers usable power approximately 100 feet away

By on September 3, 2022 0

A team of researchers from Korea’s Sejong University has presented a method to deliver useful amounts of power wirelessly over a long range – using infrared lasers to push power to gadgets up to 100 feet away. distance.

“The ability to power devices wirelessly could eliminate the need to carry power cables for our phones or tablets,” says research team leader Jinyong Ha of the problems the work could solve. “It could also power various sensors such as those in Internet of Things (IoT) devices and sensors used to monitor processes in manufacturing plants.”

Wireless power transmission isn’t new, but most systems rely on either inductive coupling or short-range radio signals between objects close enough to touch. What Ha and his colleagues have created, however, uses infrared laser light — and delivers its power over distances of up to 100 feet.

“While most other approaches require the receiving device to be in a special load cradle or to be stationary, the distributed laser load enables self-alignment without a tracking process as long as the transmitter and the receiver are in each other’s line of sight,” Ha explains. “It also automatically switches to a safe low power delivery mode if an object or person blocks the line of sight.”

The team’s prototype uses a 1,550nm laser – operating at a power low enough not to be harmful to the human eye – with a narrowband beam transmitting power to a receiver with a spherical lens retroreflector to 360 degree coverage. When the laser hits the receiver’s retroreflector, which measures just 0.4″ across, it is bounced back to a photovoltaic cell to generate electricity to power an LED.

In testing, the system was found to be able to transmit 400 mW of power over a distance of 30 meters (about 100 feet), although inefficiencies on the photovoltaic side reduced this to a usable electrical output of 85 mW – enough to to operate the LED, and potentially to drive low-power sensor systems too.

The team, however, plans to significantly increase production: “Using the laser charging system to replace power cords in factories could save maintenance and replacement costs,” predicts Ha. “This could be particularly useful in harsh environments where electrical connections can cause interference or pose a fire hazard.”

The team’s work has been published in the journal Express Optics in free access.