A future with invisibility cloaks now appears ever so slightly closer with researchers at the University of Cambridge using light as a new way to build materials.
Picture miniscule building blocks that are stacked on top of one another in layers, and connecting each block is a bridge, formed by the laser light’s reaction to the material making up the building blocks. Concentrating on these bridges, the research team has now made new discoveries in this area.
The research involves engineering materials at the nanoscale.
The team first uses barrel-shaped molecules known as cucurbiturils (CBs) which act like miniature spacers and allow a high degree of control over the spacing between the nanoparticles.
These nanoparticles need to be connected electrically and this is where the bridges come in.
Taking advantage of the precise spacing between the CBs, the researchers use laser light which focuses on the strings of nanoparticles in their CB scaffolds and produces ripples of electrons.
These ripples of electrons, known as plasmons, concentrate the light energy on atoms and join them to form the bridges between the nanoparticles.
Ultrafast lasers can result in billions of the bridges forming in rapid succession which can be monitored in real-time.
Dr Ventsislav Valev, one of the authors of the paper titled Threading plasmonic nanoparticle strings with light, commented: “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.”
The materials which researchers produce by engineering materials at the nanoscale are known as ‘metamaterials’ and these have been used previously in other areas including military stealth applications.
The research team’s use of light to construct materials at the nanoscale may help scientists to one day develop technologies such as invisibility cloaks. The team’s method also makes it possible to produce materials in higher quantities.
As developments in this area continue to be made, whether through the use of light-scattering media or the use of light in nano-construction, researchers continue to show optimism that the invisibility cloak will one day be a reality.
“However large-scale light-induced assembly remains challenging,” says Valev, so perhaps daydreams of fighting crime and practical telekinesis-related jokes will have to be kept at bay for now.
Scientists at the KIT Institute of Applied Physics in Germany recently developed technology which uses light-scattering media, such as fog or frosted glass, to make objects appear invisible.
First image courtesy of the University of Cambridge. Second image screenshot from: Harry Potter and the Sorcerer’s Stone