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!
Tracing aromatic molecules in the early universe
23.03.2017 | University of California - Riverside
New study maps space dust in 3-D
23.03.2017 | DOE/Lawrence Berkeley National Laboratory
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences