It will be possible to recharge your smartphone simply by entering a room

It will be possible to recharge your smartphone simply by

Korean researchers have succeeded in creating a “long distance” wireless charging device. Thanks to an infrared laser, the device can power devices located about thirty meters away.

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Wireless charging smartphones only works over a very short distance, requiring the user to put the device on the charger and align it correctly. Researchers from Sejong University in South Korea are proposing a new technology for charge devices which works this time on 30 meters. They published the details of their invention in the journal Optics Express.

The current is sent by a transmitter, installed on the scale of a room, consisting of an amplifier with fiber doped witherbium. It produces a ray of light infrared with a wave length central 1,550 nanometers. The receiver consists of a lens retroreflective spherical which concentrates the beam on a photovoltaic cell.

A system that charges devices from a distance of 30 meters

The device is small enough to be integrated into connected objects and even a smartphone. The infrared light must be transmitted in a straight line, without obstacles. This is the reason for choosing the retroreflective spherical lens. It returns part of the ray laserwhich facilitates alignment and allows the transmitter to switch to a low intensity mode if an object blocks the transmission, thus becoming safe for human beings.

The researchers succeeded in transmitting a beam of 400 milliwatts over 30 meters, which was converted to 85 milliwatts on arrival, i.e. an efficiency of 21.25%. This first prototype is only a proof of concept. The researchers plan to optimize the laser and increase the efficiency of the photovoltaic cell in order to be able to transmit more current over a longer distance. They also hope to adapt their device so that they can power several devices simultaneously.

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