An international team of scientists from the University of Exeter, UK, Swiss Federal Institute of Technology in Zurich (ETHZ), Switzerland, and the University of Augsburg has demonstrated how the extraordinary properties of graphene can be exploited to create artificial structures that can be used to control and manipulate electromagnetic radiation over a wide range of wavelengths.
A collaborative international team consisting of two experimental groups, led by Professor Geoffrey Nash from the University of Exeter and Professor Jérôme Faist from the Swiss Federal Institute of Technology in Zurich, and of a theoretical group of Privatdozent Dr. Sergey Mikhailov from the University of Ausgburg, have engineered and investigated a remarkable new hybrid structure, or metamaterial, that possesses specific characteristics that are not found in natural materials.
The team combined nano-ribbons of graphene together with a type of metallic antenna called a split ring resonator. Electrons in graphene are able to oscillate across the ribbon, performing so called plasma oscillations. Electrons in the metallic split-ring elements also oscillate with their own frequency.
These two types of oscillations interact with each other, with the interaction strength which can be controlled by the voltage applied between the graphene stripes and the back-side metallic contact. Careful design of these two elements leads to a system in which the hybrid plasma oscillations strongly interact with electromagnetic radiation.
As a result, the transmission of radiation through the structure can be controlled and manipulated by the electric voltage applied to it. The new structure can be thus used as a type of the terahertz-wave switch to interrupt, and turn on and off, a beam of this light very quickly.
The operation of this light modulator was demonstrated at the frequencies of several terahertz. The corresponding radiation wavelengths are very long, far beyond what the human eye can see. An important characteristic of the new structure is that it has the effect of focussing the electromagnetic radiation into an area much smaller than its wavelength. This could potentially lead to new ways of undertaking spectroscopic methods with ultra-high resolution.
The novel results obtained by the team could form the basis of a range of technologically important components. They are published in the respected scientific journal Nature Communications. This research work was carried out within the European FET Open Project GOSFEL ( www.gosfel.eu ), which aims to develop an entirely new laser source for many different applications in security, medicine, telecommunication, gas sensing, and so on. The Augsburg group also investigates nonlinear electrodynamic properties of graphene within another, large European research Program Graphene Flagship, with the goal to use them in different electronic and optoelectronic applications.
Peter Q. Liu, Isaac J. Luxmoore, Sergey A. Mikhailov, Nadja A. Savostianova, Federico Valmorra, Jerome Faist, Geoffrey R. Nash, “Highly tunable hybrid metamaterials employing split-ring resonators strongly coupled to graphene surface plasmons”, Nature Communications 6, 8969 (2015).
PD Dr. Sergey Mikhailov
Institut für Physik der Universität Augsburg
Klaus P. Prem Presse | idw - Informationsdienst Wissenschaft
Researchers printed graphene-like materials with inkjet
18.08.2017 | Aalto University
Superconductivity research reveals potential new state of matter
17.08.2017 | DOE/Los Alamos National Laboratory
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences