Researchers from Washington University have developed a new technology that makes it possible to remotely charge the battery of a smartphone or other electronic device located anywhere in the room, using a beam of laser light. Due to a number of measures taken, this method of charging is absolutely safe and uses a thin beam of invisible laser light, which carries a sufficient amount of energy.
The new laser system, according to its developers, is able to charge the phone battery as quickly as through a normal USB cable connected to a charger. To allow the phone to “collect” the light of the laser beam, the researchers installed a thin photovoltaic cell mounted on a metal heat sink on the back cover. A miniature corner reflector is also attached there, which returns the beam of light from the “signal” laser, allowing the main laser to turn off if a person enters the energy transfer area.
The researchers say that safety was key in the development of this system. And they managed to find a solution that is effective enough to allow the laser charging method to be used in relation to a wide range of household and consumer electronic devices.
The system uses several signal beams, which surround the main energy-carrying beam from all sides. These signal beams contain very small amounts of energy and are therefore completely safe for humans. The protection system based on them operates almost at the speed of light and the system reacts to interruption of these beams much faster than any human can move.
The experimental system is capable of supplying an electronic device with up to 2 watts of power continuously, covering an area of 15 square inches at a distance of up to 14 feet (4.3 meters). But the system can be just as effective up to 12 meters away by making minor modifications to the optical system of the main laser, which emits light in the invisible infrared range.
Finally, it should be noted that the red beams of light visible in the above images were made visible only for the purpose of demonstrating the principles of the laser charging system. In fact, both the main laser light beam and the beams of the signal lasers are completely invisible to the human eye.
