Wirelessly transmitted power over 30 m of thin air

Researchers have used infrared laser light to transmit 400 mW of light power over distances of up to 30 m. That's enough juice to charge small sensors.

The technical term for it is distributed laser charging, and the particular type developed here manages to be safer and able to go further than previous experiments with similar sort of wireless power transmission technologies.

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.

In the experimental setup, an amplifier transmitter specially treated with a silvery white metal called erbium was set up 30 meters away from the receiver, which was outfitted with a photovoltaic cell to convert the light signal into electrical power.