Invisibility Cloak 'Metamirrors' Can Turn Into Windows
We've gotten one step closer to real-life invisibility cloaks using artificially engineered metamaterials, and now that same technology may allow us to create "metamirrors" that can turn into windows depending on the color of the light hitting them.
Metamaterials are artificially engineered materials, specifically created to have properties that cannot be found in nature. The geometry and orientation that results from the materials being arranged in artificially exact repeating patterns allows them to interact with light and sound in unconventional ways. As a result, they are theoretically able to bend light around an object, rendering it effectively "invisible."
For this new study, Viktar Asadchy of Aalto University and his research team decided to apply metamaterial technology to mirrors, creating "metamirrors" that can bend light in idiosyncratic ways. While conventional mirrors follow the simple reflection law that a wave is reflected back at the same angle, the metamirrors were able to bounce back microwaves at 45 degree angles.
"We have small antennas in our device and they reflect the wave differently. We can change the wavefront of the light, which means you can change the direction," Asadchy told New Scientist.
Each metamirror is built to function with a certain wavelength, which means that the mirror would be "invisible" to every other wavelength. So hypothetically, if the metamirror corresponded to the wavelength associated with blue light, then the glass would be a metamirror when it came into contact with blue light and would serve as a transparent window when interacting with light of any other color.
In addition to building color-specific mirror/window hybrids, the researchers believe that this technology could have a myriad of other applications. For example, they discuss the possibility that solar panels on satellites could be coated with metamirror material imbued with radio capability, which would allow for sunlight to shine through to the panels while also serving as a means of radio communication and saving room on the craft.