Spanish research groups achieve first ever visualizations of light guided with nanometric precision on graphene (a one-atom-thick sheet of carbon atoms). This visualization proves what theoretical physicists have long predicted; that it is possible to trap and manipulate light in a highly efficient way, using graphene as a novel platform for optical information processing and sensing.
Synergies between theoretical proposals from IQFR-CSIC (Madrid), specializations in graphene nano-photonics and nano-optoelectonics at ICFO (Barcelona), and experimental expertise in optical nano-imaging at nanoGUNE (San Sebastian) give rise to these noteworthy results reported in Nature this week in a back-to-back publication alongside a similar study by the group of Dmitry Basov in UCSD in California.
Graphene is a material that, among many other fascinating properties, has an extraordinary optical behavior. Particularly interesting optical properties had been predicted for the case that light couples to so-called plasmons, wave-like excitations that were predicted to exist in the "sea" of conduction electrons of graphene. However, no direct experimental evidence of plasmons in graphene had been shown up to this work. This is because the wavelength of graphene plasmons is 10 to 100 times smaller than what can be seen with conventional light microscopes. Now, the researchers show the first experimental images of graphene plasmons.
They used a so called near-field microscope that uses a sharp tip to convert the illumination light into a nanoscale light spot that provides the extra push needed for the plasmons to be created. At the same time the tip probes the presence of plasmons (see figure). Rainer Hillenbrand, leader of the nanoGUNE group comments: "Seeing is believing! Our near-field optical images definitely proof the existence of propagating and localized graphene plasmons and allow for a direct measurement of their dramatically reduced wavelength."
As demonstrated by the researchers, graphene plasmons can be used to electrically control light in a similar fashion as is traditionally achieved with electrons in a transistor. These capabilities, which until now were impossible with other existing plasmonic materials, enable new highly efficient nano-scale optical switches which can perform calculations using light instead of electricity. "With our work we show that graphene is an excellent choice for solving the long-standing and technologically important problem of modulating light at the speeds of today's microchips," says Javier García de Abajo, leader of the IQFR-CSIC group. In addition, the capability of trapping light in very small volumes could give rise to a new generation of nano-sensors with applications in diverse areas such as medicine and bio-detection, solar cells and light detectors, as well as quantum information processing.
This result literally opens a new field of research and provides a first viable path towards ultrafast tuning of light, which was not possible until now. Frank Koppens, leader of the ICFO group, summarizes: "Graphene is a novel and unique material for plasmonics, truly bridging the fields of nano-electronics and nano-optics".
Published manuscript:Optical nano-imaging of gate-tunable graphene plasmons Jianing Chen, Michela Badioli, Pablo Alonso-González, Susokin Thongrattanasiri, Florian Huth, Johann Osmond, Marko Spasenoviæ, Alba Centeno, Amaia Pesquera, Philippe Godignon, Amaia Zurutuza, Nicolas Camara, Javier García de Abajo, Rainer Hillenbrand & Frank Koppens
Aitziber Lasa Iglesias | EurekAlert!
21.03.2019 | Max-Planck-Institut für Polymerforschung
Levitating objects with light
19.03.2019 | California Institute of Technology
Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.
The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...
Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.
Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...
Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.
"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...
New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum
For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...
11.03.2019 | Event News
01.03.2019 | Event News
28.02.2019 | Event News
21.03.2019 | Life Sciences
21.03.2019 | Physics and Astronomy
21.03.2019 | HANNOVER MESSE