A team of physicists, headed by the U.S. Naval Research Laboratory (NRL), have demonstrated the means to improve the optical loss characteristics and transmission efficiency of hexagonal boron nitride devices, enabling very small lasers and nanoscale optics.
"The applications for this research are considerably broad," said Dr. Alexander J. Giles, research physicist, NRL Electronics Science and Technology Division. "By confining light to very small dimensions, nanophotonic devices have direct applications for use in ultra-high resolution microscopes, solar energy harvesting, optical computing and targeted medical therapies."
Image shows directly measured polaritons propagating through a flake of Hexagonal boron nitride (hBN). This material has been identified as an ideal substrate for two-dimensional materials research while also recently being demonstrated as an exciting optical material for infrared nanophotonics.
Credit: (US Naval Research Laboratory)
Hexagonal boron nitride (hBN) forms an atomically thin lattice consisting of boron and nitrogen atoms. This material has recently been demonstrated as an exciting optical material for infrared nanophotonics and is considered an 'ideal substrate' for two-dimensional materials.
While previous work demonstrated that natural hBN supports deeply sub-diffractional hyperbolic phonon polaritons desired for applications, such as, sub-diffractional optical imaging (so-called 'hyperlensing'), energy conversion, chemical sensing, and quantum nanophotonics, limited transmission efficiencies continue to persist.
"We have demonstrated that the inherent efficiency limitations of nanophotonics can be overcome through the careful engineering of isotopes in polar semiconductors and dielectric materials," Giles said.
Naturally occurring boron is comprised of two isotopes, boron-10 and boron-11, lending a 10 percent difference in atomic masses. This difference results in substantial losses due to phonon scattering, limiting the potential applications of this material. The research team at NRL has engineered greater than 99 percent isotopically pure samples of hBN, meaning they consist almost entirely of either boron-10 or boron-11 isotopes.
This approach results in a dramatic reduction in optical losses, resulting in optical modes that travel up to three times farther and persist for up to three times longer than natural hBN. These long-lived vibrational modes not only enable immediate advances specific to hBN - near field optics and chemical sensing - but also provide a strategic approach for other materials systems to exploit and build upon.
"Controlling and manipulating light at nanoscale, sub-diffractional dimensions is notoriously difficult and inefficient," said Giles. "Our work represents a new path forward for the next generation of materials and devices."
Contributors to this research include scientists from the University of California San Diego, Kansas State University, Oak Ridge National Laboratory, Columbia University, and Vanderbilt University. Full details of this research entitled "Ultralow-loss polaritons in isotopically pure boron nitride," can be found in the December 11, 2017 edition of Nature Materials (doi:10.1038/nmat5047).
Daniel Parry | EurekAlert!
Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1
21.03.2018 | Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR
Taming chaos: Calculating probability in complex systems
21.03.2018 | American Institute of Physics
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