Near-IR laser system safely charges a smartphone wirelessly from across a room
This laser-based wireless charging system was created by University of Washington engineers. The charging laser and guard lasers are normally invisible to the human eye, but red beams have been inserted here in place of the guard beams for demonstration purposes. Researchers at the University of Washington (Seattle, WA) have designed and experimentally demonstrated a laser-based line-of-sight wireless power delivery system that could be used, for example, for charging smartphones and other devices.1 The researchers say that the system delivers more than 2 W of power safely over distances of 4.3 and 12.2 m for a smartphone (25 cm2) and tabletop form factor (100 cm2) receiver, respectively. The system uses a high-power laser-diode source with a 978 nm wavelength, along with two steerable mirrors to aim the beam at the receiver; a photovoltaic cell, heatsink, and retroreflector at the receiver; and a low-power guard laser beam to serve as a safety interlock (using the retroreflector),...