Invisibility, black butterflies and meta-mirrors. I’m Rich Northrup, and in this week’s edition of the Engineering360 news brief we’ll be talking about some of the most interesting happenings in engineering around light.
At Ben-Gurion University in Israel, researchers have achieved a breakthrough in manipulating light in order to render an object invisible. According to a recent study, the researchers have conceived a new method of deflecting and scattering light away from the surface of an optical chip. This kind of “cloaking” could work as an extension of technologies like optical camouflage and the radar-absorbing paint used on stealth aircraft. Light deflection could also be used to scatter electromagnetic waves, or to cool surfaces by minimizing electromagnetic infrared emissions. Read more.
On the other side of the spectrum, researchers at the Karlsruhe Institute of Technology in Germany aren’t looking to reflect light away, but absorb more of it. Solar cells reflect some of the light they are exposed to, which means that its potential to generate energy is lost. In order to increase light absorption, the researchers took a cue from a black swallowtail butterfly common in Asia. The butterfly’s wings contain tiny holes that help to absorb a wide spectrum of light. By mimicking the butterfly’s nanostructures in thin-film solar cells, they’ve managed to increase the light absorption rate by up to 200 percent. Read more.
A new type of mirror that reflects light in a completely different way could find use in information processing with light, as well as next-generation 3D movies. Designed by researchers at the Georgia Institute of Technology, the “chiral meta-mirror” preserves the spin state of light with circular polarization — the same type of light that is interpreted by 3D glasses to create the illusion of depth. In a conventional mirror, the spin state is reversed and reflected back in the opposite direction. By preserving spin state instead, it’s possible to perform photonic information processing on spins used to carry data. Read more.