For the first time, light is confined to an atom

The graphene is ensured that the material of the future for its amazing properties. Not only is it the finest that exists, but it is also very flexible and lightweight, but harder than steel, which makes it possible to create structures that are very light and resistant at the same time. It is also capable of guiding light, so it can be used to make ultrathin and tiny electronic devices.

In this regard, researchers from the Institute of Photonic Sciences (ICFO) in Barcelona have achieved thanks to graphene a milestone in science: confine the light in a single atom thick, smallest possible confinement. In addition to the scientific relevance of this finding, they open the door to be able to manufacture ultra sensitive and small optical sensors, as well as detectors, switches, ultrafast chips. The devices, in short, that we will carry in our pocket in the future.

“Traditionally, researchers have tried to confine light using metals. What happens is that the more you try to confine it, the more energy losses you have. Below 15 or 20 nanometers, there is no light, it can not spread. We have managed to overcome this paradigm, ” ICF researcher Frank Koppens of ICFO, who led the study, explains in an interview with Big Vang. “We have discovered that using graphene we can confine light more strongly and without additional losses,” he says.

Since the Bell Laboratories invented the transistor, at the end of the 40s of the last century, it is the main piece of electronic devices. All current devices, from computers to mobile phones, are made up of billions of transistors. Research has made it possible for these transistors to be increasingly smaller: they have gone from one centimeter, which is what the first ones measured, to 14 nanometers, the size of the current ones. And with them, too, the size of the devices.

The problem is that, until now, it seemed that we had reached a limit. You could not keep reducing the size of computer chips to continue making thinner and lighter devices: every time you tried to push the light below the diffraction limit, so much energy was lost that the light stopped spreading. The discovery of ICFO changes this situation.

Thanks to graphene

It was already known that graphene was able to guide light in the form of plasmons, which are oscillations of electrons that act very strongly with light. What the ICFO researchers have done is to use two layers of two-dimensional materials, one of graphene and one metal, as well as an insulator, with which they have built a nano-optical device capable of guiding light without additional losses.


“At the beginning, we were looking for a new way to excite graphene plasmons,” says David Alcaraz Iranzo, first author of ICFO’s work, in a press release. “But we discovered that the confinement of the light was stronger than before with minimal energy losses. So we decided to go to the limit of an atom and we got these amazing results. ”

The discovery is an important step forward in designing new lightweight and ultra-thin devices. According to Koppens, since the light is so confined, it is ultrasensitive and would allow manufacturing extremely small and sensitive sensors, which could be located even in chips. Also, create new devices that combine electronics and photonics.

“We always think of light as something we can see but in the future, it will be integrated into the optics in the chips: it will be generated in them, manipulated in them, detected in them. This work is a paradigm shift, scientific because nobody expected this to happen, and also in terms of applications, “concludes Koppens.

This study has been published in the journal Science and has also involved researchers from the Massachusetts Institute of Technology (MIT) and the University of Minho (Portugal)