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!
Beyond the brim, Sombrero Galaxy's halo suggests turbulent past
21.02.2020 | NASA/Goddard Space Flight Center
10,000 times faster calculations of many-body quantum dynamics possible
21.02.2020 | Christian-Albrechts-Universität zu Kiel
The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.
Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...
Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.
Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...
Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices
The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...
Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.
Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.
After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.
"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.
12.02.2020 | Event News
16.01.2020 | Event News
15.01.2020 | Event News
24.02.2020 | Life Sciences
24.02.2020 | Materials Sciences
24.02.2020 | Earth Sciences