It's the stuff of science fiction films. Imagine charging your phone or laptop without ever plugging it. Instead, a force from across a room beams energy directly to your devices.
That dream might soon become a reality thanks to a new invention called "anti-laser." The study, published in the journal Nature Communications, reveals that this anti-laser can beam power with 99.996% efficiency to devices no matter how crowded a room is.
This is important because a room's status was one of the key obstacles to the device working in the past. Indeed, a real-life environment is much more complex than a lab with walls that reflect energy; in the real world, some objects hinder energy from moving around and other electronics often get in the way too.
Coherent perfect absorption
The method these scientists used is called "coherent perfect absorption" (CPA) and it involves having one machine send power across the room, and another suck it back up. In this case, it is the anti-laser that does the sucking.
"Coherent perfect absorption (CPA) has been appealing to physicists and engineers for both its fundamental and technological relevance. On the technological level, its implementation promises the realization of a family of wave-based devices performing highly-selective and tunable absorption in a manner that goes beyond the traditional concept of impedance matching," wrote the researchers in their study.
"On the fundamental level, CPA has initially been associated with the concept of time-reversal (TR) symmetry, one of the most fundamental symmetries in nature."
Time reversal symmetry, situations where time could flow as easily backward as forward, initially had to exist for the anti-laser to work. This was problematic as such circumstances are difficult to recreate.
However, for this experiment, the scientists jostled the photons so aggressively that time reversal symmetry was lost and the anti-laser still worked! This "proves that the concept of CPA goes far beyond its initial conception as a 'time-reversed laser,'" further wrote their researchers in their study, implying that their anti-laser innovation could one day work in real life.