14 DAY TRIAL // Thanks to researchers with the University of Cambridge in the UK, there might come a day when ordinary folks will get to strut around in invisibility cloaks like the one described in “Harry Potter.” The only downside is that nobody will get to see them doing so.
Thus, a paper published in the journal Nature Communications just yesterday details a technique to develop novel materials built with light that scientists say could pave the way to technologies that make things invisible to the naked eye.
In a press release concerning this breakthrough, University of Cambridge scientists explain that the key to developing materials that could function as invisibility cloaks is toying with the way in which light interacts with the surfaces it hits.
The specialists say that, when coming into contact with one surface or another, light is either absorbed of reflected. This makes it possible for us to see objects. They further detail that, by controlling the way light interacts with them, certain materials can render objects invisible.
The technique developed by the University of Cambridge researchers boils down to piecing together nanoparticles whose width is roughly the same as that of a strand of DNA, i.e. a few billionths of a meter, information shared with the public says.
The resulting structures can serve to bend light in such ways so as to make an object hidden under them invisible, the scientists write in the journal Nature Communications. Specifically, materials obtained using this technique can ensure invisibility by refracting light in unusual directions.
“Light reflected by a metamaterial [i.e. a material able to control the way light interacts with it] is refracted in the ‘wrong’ way, potentially rendering objects invisible, or making them appear as something else,” the researchers explain in the press release documenting this research project.
Looking to develop such metamaterials, the University of Cambridge specialists used light to engineer rather long strings using gold nanoparticles as building blocks. These strings were then neatly placed one on top of the other to obtain larger structures.
The achievement was made possible by the use of a scaffold comprising molecules dubbed cucurbiturils, which helped ensure adequate spacing between the nanoparticles. The lasers fired at these structures birthed ripples of electrons that served to connect the nanoparticles.
“The technique developed by the Cambridge team involves using unfocused laser light as billions of needles, stitching gold nanoparticles together into long strings, directly in water for the first time,” the scientists detail their technique.
Furthermore, “These strings can then be stacked into layers one on top of the other, similar to Lego bricks. The method makes it possible to produce materials in much higher quantities than can be made through current techniques.”
The bad news is that, breakthrough aside, it will probably be a while before invisibility cloaks hit supermarket shelves. This is because scientists are yet to figure out a way to scale up this technique of using light to make metamaterials capable of making objects invisible to the naked eye.
“Joining a few nanoparticles together is fine, but scaling that up is challenging,” explains Dr. Ventsislav Valev of the University’s Cavendish Laboratory. Still, the scientist and colleagues is convinced it's only a matter of time until invisibility cloaks come our way.
“We have controlled the dimensions in a way that hasn’t been possible before. This level of control opens up a wide range of potential practical applications,” Dr. Ventsislav Valev comments on the importance of the technique and experiments described in the journal Nature Communications.