Gems are known for the beauty of the light that passes through them. But it is the fixed atomic arrangements of these crystals that determine which light frequencies are permitted passage.
Now a Sandia-led team has created a plasmonic, or plasma-containing, crystal that is tunable. The effect is achieved by adjusting a voltage applied to the plasma, making the crystal agile in transmitting terahertz light at varying frequencies. This could increase the bandwidth of high-speed communication networks and generally enhance high-speed electronics.
“Our experiment is more than a curiosity precisely because our plasma resonances are widely tunable,” says Sandia researcher Greg Dyer, co-primary investigator of a recently published online paper in Nature Photonics, expected to appear in print in that journal in November. “Usually, electromagnetically induced transparencies in more widely known systems like atomic gases, photonic crystals and metamaterials require tuning a laser’s frequencies to match a physical system. Here, we tune our system to match the radiation source. It’s inverting the problem, in a sense.”
The plasmonic crystal method could be used to shrink the size of photonic crystals, which are artificially built to allow transmission of specific wavelengths, and to develop tunable metamaterials, which require micron- or nano-sized bumps to tailor interactions between manmade structures and light. The plasmonic crystal, with its ability to direct light like a photonic crystal, along with its sub-wavelength, metamaterial-like size, in effect hybridizes the two concepts.
The crystal’s electron plasma forms naturally at the interface of semiconductors with different band gaps. It sloshes between their atomically smooth boundaries that, when properly aligned, form a crystal. Patterned metal electrodes allow its properties to be reconfigured, altering its light transmission range. In addition, defects intentionally mixed into the electron fluid allow light to be transmitted where the crystal is normally opaque.
However, this crystal won’t be coveted for the beauty of its light. The crystal transmits in the terahertz spectrum, a frequency range invisible to the human eye. Scientists also must adjust the crystal’s two-dimensional electron gas to electronically vary its output frequencies, something casual crystal buyers probably won’t be able to do.
Following online release, the paper titled, “Induced transparency by coupling of Tamm and defect states in tunable terahertz plasmonic crystals,” is slated to appear in the November print edition of Nature Photonics.
In addition to Dyer, other authors are co-principal investigator Eric Shaner, with Albert D. Grine, Don Bethke and John L. Reno, all from Sandia; Gregory R. Aizin of The City University of New York; and S. James Allen of the Institute for Terahertz Science and Technology at the University of California, Santa Barbara.
The work was supported by the Department of Energy’s Office of Basic Energy Sciences (BES) and performed in part at the Center for Integrated Nanotechnologies (CINT), a Sandia/Los Alamos national laboratories user facility that is is one of the five DOE Nanoscale Science Research Centers.
Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies and economic competitiveness.
Neal Singer | Newswise
The search for dark matter widens
21.03.2018 | American Institute of Physics
Scientists have a new way to gauge the growth of nanowires
19.03.2018 | DOE/Argonne National Laboratory
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
21.03.2018 | Physics and Astronomy
21.03.2018 | Materials Sciences
21.03.2018 | Life Sciences