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Scientists have found a way to perfectly diffuse energy throughout any room, thanks to a sci-fi-type device they call an “anti-laser.”
The idea is simple: just like a laser emits particles of light, or photons, one after another in a neat, orderly row, an anti-laser sucks photons one after the other in reverse order. Researchers have long believed that a device like this could make charging wires and cables a thing of the past, allowing people to transmit energy invisibly through a room to a laptop or phone. and power it without plugging it in. But although basic anti-lasers have tested before, the real world isn’t as crisp and tidy as a laser pointed at a stationary receiver in a lab. Electronics move, objects get in the way, walls reflect energy in unexpected ways. The new anti-laser demonstrated in this experiment explains all of this, and it receives energy scattered through space in an unpredictable pattern – still receiving 99.996% of the power sent.
The formal term for the method used is “coherent perfect absorption” (CPA). The CPA uses one machine to send energy through the room and another (“anti-laser”) to suck it up. Past experiences of the CPA, the researchers wrote in an article published Nov. 17 in the journal Nature communications, were exciting but had one fundamental limitation: the direction of time. The experiments only worked in situations where time could flow backward as easily as it did forward, something that rarely exists in our everyday life.
Related: 8 ways to see Einstein’s theory of relativity in real life
The simplest model of an anti-laser setup, involving a laser pointer firing photons one after another into a receptor that engulfs them, would basically look the same if you played a soundtrack of its action towards the ‘forward or backward: the photon leaves one device, travels through space and enters the other device. It is said that configurations like this, in terms of physics, have “time inversion symmetry”. Time inversion symmetry only appears in systems without much entropy, or the inherent tendency of systems to fall into disarray.
So far, even the most complex CPA experiments have had time reversal symmetry. Some were more complex than the laser pointer pointed at a receiver. But even complex projects have this symmetry if they are set up in such a way that the process can be reversed.
(Here’s an example of how a complicated event can be time-inverted symmetrical: Imagine a videotape of an amateur picking up Lego pieces from a neat case and using them to build a model of the Eiffel Tower. The result. would look complicated, but the tape would be recording where each song went, so playing the tape backwards would just show the hobbyist to take the pieces apart and organize them again.)
But for this new work, the researchers used magnetic fields jostling the photons so aggressively that the time inversion symmetry has been lost. The process of power transfer – shooting the photons – was like stirring soup: it doesn’t work backwards. (Imagine trying to stir the soup.) But the device still received power.
This “proves that the concept of CPA goes far beyond its initial conception as a” time-inverted laser, “” the researchers wrote in their paper, suggesting that it may one day have practical applications in the field. real world. This is because the real world is not as sharp as a time-reversible lab experiment. It’s messy and unpredictable, and never reversible over time over the long term. For the CPA to work in these difficult conditions, it must be able to cope with them.
The researchers achieved this inverted non-temporal APC in two experimental setups, both using microwave energy. The first was a “labyrinth” of wires that photons had to travel through to reach a receptor. The second was a small, irregular “brass cavity” with a receptor in the middle, which photons reached after scattering and passing through the open space of the cavity.
To achieve this, the researchers emitted microwaves of different properties and tested which combination of frequencies, amplitudes, and phases (three characteristics of any electromagnetic wave) was most likely to land on the receiver and be absorbed – even after passing through magnetic fields. and the labyrinth or irregular open space. In each case, they determined an ideal “match” of the microwave emitter that caused absorption of most microwaves (99.999% in the maze, 99.996% in the open space). In real world applications (like your living room), the transmitter would test and retest different frequencies, amplitudes, and phases to transfer photons to its receiver.
There are three major potential applications of this technology. The first is remote wireless energy transfer, the researchers wrote. (Goodbye plugging in your laptop.) Another is a sensing device that could detect subtle changes in any room where photons are scattered. (Imagine a security camera that can sense an intruder moving around a room.)
The third is a messaging system that could securely transfer information to a hidden receiver; signals sent via CPA could use the constantly changing setting numbers as a kind of password to encrypt the data. Only the recipient or someone who knew the recipient’s exact behavior at all times could decrypt the message.
Such real-world uses are still a long way off. But this experiment shows that they are at least possible, the researchers wrote.
Originally posted on Live Science.
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