A team of researchers has allowed people to control metasurfaces using their thoughts. Their results are published in the journal eLight under the pleasing title "remotely mind-controlled metasurface via brainwaves".
Metasurfaces, for the uninitiated, have nothing to do with Facebook's terrible new name. Metamaterials are substances that have properties that do not occur naturally. The man-made materials interact with sound and electromagnetic waves (including light) in ways not seen in conventional materials.
“The idea behind metamaterials is to mimic the way atoms interact with light, but with artificial structures much smaller than the wavelength of light itself,” Boris Kuhlmey from the University of Sydney explained to The Conversation. “This way, optical properties are no longer restricted to those of the constituent materials, and can be designed almost arbitrarily.”
The materials and their 2D counterpart "metasurfaces" have countless applications, from medical devices to invisibility cloaks.
In a new experiment, led by Professor Shaobo Qu & Professor Jiafu Wang from Air Force Engineering University and Professor Cheng-Wei Qiu from the National University of Singapore, scientists have shown how these metamaterials can be controlled with surprising precision remotely, using signals from users' minds.
The team first created a metamaterial that could manipulate and adjust the scattering of light by altering the current flowing through it. Next, they used a commercial brainwave sensor module to "collect and then send brainwaves wirelessly towards the [remotely mind-controlled metasurface]" via bluetooth.
"Upon the incoming brainwaves," the team wrote in their paper, "the [remotely mind-controlled metasurface] will respond by changing its [light] scattering pattern. In this way, the metasurface can be remotely controlled by the user’s mind."
In an extra level of cool, the control wasn't as simple as merely alternating through two different patterns of scattering.
"Using brainwave signals sent to [the control unit] as the control signal, the coding sequences on the metasurface can be altered according to the user’s attention intensity," the team continued. "In this way, the scattering pattern of the metasurface can be controlled remotely via the user’s mind."
Using different intensities of thought – detectable by the brainwave sensor module – users can create several different light scatter patterns on the metamaterial itself. As well as one obvious use – a neat visual measure of attention and concentration – the team believes controlling metamaterials in this way could have several real-world applications.
"Combined with intelligent algorithms such as machine learning, the intelligent process of the system will be further improved," the team concluded. "This work can be readily extended to other mind-controlled functional or multi-functional metasurfaces and may find applications in health monitoring, 5G/6G communications, smart sensors, etc."