Even though mobile devices such as tablets and smartphones let us communicate, work and access information wirelessly, their batteries must still be charged by plugging them into an outlet. To overcome this, engineers have developed a method through which we can charge our phone wirelessly through laser across the room.
They discovered that a narrow, invisible beam from a laser emitter can deliver charge to a smartphone sitting across a room and can potentially charge a smartphone as quickly as a standard USB cable.
To accomplish this, the team mounted a thin power cell to the back of a smartphone, which charges it using power from the laser. To dissipate the excess heat from the laser, they have a custom-designed safety feature which includes a metal, flat plate heat sink on the smartphone.
In addition to that.the system has a reflector based mechanism to shut of the laser if a person tries to enter in the charging beam’s path. “These features give our wireless charging system the robust safety standards needed to apply it to a variety of commercial and home settings,” said Arka Majumdar, a researcher in the UW in their news release.
The charging beam is generated by a laser emitter that the team configured to produce a focused beam in the near-infrared spectrum. The safety system that shuts off the charging beam centres on low-power, harmless laser guard beams, which are emitted by another laser source co-located with the charging laser-beam and physically “surround” the charging beam.
The researchers programmed the smartphone to signal its location by emitting high-frequency acoustic chirps. These are inaudible to our ears, but sensitive enough for small microphones on the laser emitter to pick up.“This acoustic localization system ensures that the emitter can detect when a user has set the smartphone on the charging surface, which can be an ordinary location like a table across the room,” said co-lead author Vikram Iyer, a UW doctoral student in electrical engineering.
When the emitter detects the smartphone on the desired charging surface, it switches on the laser to begin charging the battery.The beam delivers charge as quickly as plugging in your smartphone to USB port but instead of plugging in you are just placing it on the surface.