A thin beam of invisible laser light has been used to safely charge a smartphone across a room. The experiment by researchers at the Univeristy of Washington lends credence to the futuristic idea that one day all computers could operate without any plugs or wires \u2014 that\u2019s both for data and power.\nThe revolutionary smartphone-charging laser system, which functions from up to 40 feet away, detects devices through inaudible acoustic chirps, according to its desginers at\u00a0the university. It then zaps a couple watts of power at them using laser beams. Importantly, it does it safely and is potentially scalable to computers.\nIf one were to add to this news the speculation that there may soon be a shift away from traditional Ethernet to 5G wireless for infinitely fatter and faster data networks, then conceivably the end of all physical connections between computers may become a reality in the not-too-distant future.\n\nCharging over the air, called Wireless Power Transfer (WPT), is in use now at short ranges, using coils and magnetic fields. We see WPT in inductive consumer charging systems such as toothbrushes and smartphones, for example.\nHowever, range is limited. To send power over longer distances, or to provide more power, a radiative power-beaming transmission form is needed, such as a laser or microwave. The problem with that, though, is those are hazardous to humans \u2014 you can\u2019t allow people to get in the path of the beam.\nThe University of Washington researchers say they have solved that major safety problem.\n\u201cThe laser emitter will terminate the charging beam before a person comes into the path of the laser,\u201d says Shyam Gollakota, an associate professor at the institution\u2019s Paul G. Allen School of Computer Science & Engineering and one of the developers, in a news release published by the university.\nThe group claims to be able to shut down the laser when someone crosses the path, and to do it so quickly there no chance that the person becomes injured. They achieve this through the use of what they call a \u201crapid-response safety mechanism,\u201d which ingeniously uses low-power, guard laser beams to surround the principal high-power beam. If the low-power sensor beams become interrupted, the adjacent main beam is quickly shut down before injuries can occur.\n\u201cThe guard beams are able to act faster than our quickest motions because those beams are reflected back to the emitter at the speed of light,\u201d claims Gollakota. The researchers say the human subject would have to be traveling at more than 98 miles per hour before the system might fail to turn off.\n\u201cDelivering greater than a watt of power across the room, minimizing the exposure of the resulting high-power lasers to human tissue, and finally ensuring that the design meets the form-factor requirements of a smartphone\u201d are satisfied, the team claims in an abstract of their paper.\nAnd it \u201ccan potentially charge a smartphone as quickly as a standard USB cable,\u201d they say.\nAdditionally, \u201cwireless, laser-based charging of other devices, such as cameras, tablets, and even desktop computers,\u201d could all be possible, the researchers say.\nAdd wireless data to that mix, and for the first time, its possible eventually there will be no umbilical cords at all for computing.