Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists apply 'twistronics' to light propagation and make a breakthrough discovery

15.06.2020

The findings provide a promising pathway for leapfrog advancement in imaging, optical-computing technologies, biosensing and more

A research team led by scientists at the Advanced Science Research Center at The Graduate Center, CUNY (CUNY ASRC), in collaboration with National University of Singapore, University of Texas at Austin and Monash University, has employed "twistronics" concepts (the science of layering and twisting two-dimensional materials to control their electrical properties) to manipulate the flow of light in extreme ways. The findings, published in the journal Nature, hold the promise for leapfrog advances in a variety of light-driven technologies, including nano-imaging devices; high-speed, low-energy optical computers; and biosensors.


A bilayer of molybdenum trioxide supports highly unusual light propagation along straight paths when the two layers are rotated with respect to each other at the photonic magic angle.

Credit: ASRC

Usage Restrictions: For use only in conjunction with coverage of this research.

The team took inspiration from the recent discovery of superconductivity in a pair of stacked graphene layers that were rotated to the "magic twist angle" of 1.1 degrees. In this configuration, electrons flow with no resistance. Separately, each graphene layer shows no special electrical properties. The discovery has shown how the careful control of rotational symmetries can unveil unexpected material responses.

The research team discovered that an analogous principle can be applied to manipulate light in highly unusual ways. At a specific rotation angle between two ultrathin layers of molybdenum trioxide, the researchers were able to prevent optical diffraction and enable robust light propagation in a tightly focused beam at desired wavelengths.

Typically, light radiated from a small emitter placed over a flat surface expands away in circles very much like the waves excited by a stone that falls into a pond. In their experiments, the researchers stacked two thin sheets of molybdenum trioxide -- a material typically used in chemical processes -- and rotated one of the layers with respect to the other. When the materials were excited by a tiny optical emitter, they observed widely controllable light emission over the surface as the rotation angle was varied. In particular, they showed that at the photonic magical twist angle the configured bilayer supports robust, diffraction-free light propagation in tightly focused channel beams over a wide range of wavelengths.

"While photons -- the quanta of light -- have very different physical properties than electrons, we have been intrigued by the emerging discovery of twistronics, and have been wondering if twisted two-dimensional materials may also provide unusual transport properties for light, to benefit photon-based technologies," said Andrea Alù, founding director of the CUNY ASRC's Photonics Initiative and Einstein Professor of Physics at The Graduate Center. "To unveil this phenomenon, we used thin layers of molybdenum trioxide. By stacking two of such layers on top of each other and controlling their relative rotation, we have observed dramatic control of the light guiding properties. At the photonic magic angle, light does not diffract, and it propagates very confined along straight lines. This is an ideal feature for nanoscience and photonic technologies."

"Our discovery was based on quite a specific material and wavelength range, but with advanced nanofabrication we can pattern many other material platforms to replicate these unusual optical features over a wide range of light wavelengths," said National University of Singapore (NUS) graduate student Guangwei Hu, who is first author of the study and a long-term visiting researcher with Alù's group. "Our study shows that twistronics for photons can open truly exciting opportunities for light-based technologies, and we are excited to continue exploring these opportunities," said Prof. C.W. Qiu, Mr. Hu's co-advisor at NUS.

###

The research team consisted of scientists from CUNY ASRC, National University of Singapore, University of Texas at Austin and Monash University. Their work was supported by an Air Force Office of Scientific Research MURI grant, the Office of Naval Research, the Department of Defense Vannevar Bush Fellowship Program, and the National Science Foundation.

About the Advanced Science Research Center

The ASRC elevates scientific research and education at CUNY and beyond through initiatives in five distinctive, but increasingly interconnected disciplines: environmental sciences, nanoscience, neuroscience, photonics, and structural biology. The ASRC promotes a collaborative, interdisciplinary research culture with renowned researchers from each of the initiatives working side-by-side in the ASRC's core facilities, sharing equipment that is among the most advanced available.

About The Graduate Center of The City University of New York

The Graduate Center of The City University of New York is a leader in public graduate education devoted to enhancing the public good through pioneering research, serious learning, and reasoned debate. The Graduate Center offers ambitious students more than 40 doctoral and master's programs of the highest caliber, taught by top faculty from throughout CUNY -- the world's largest public urban university. Through its nearly 40 centers, institutes, and initiatives, The Graduate Center influences public policy and discourse and shapes innovation. The Graduate Center's extensive public programs make it a home for culture and conversation.

Media Contact

Shawn Rhea
srhea@gc.cuny.com
504-905-9888

 @asrc_gc

http://asrc.cuny.edu 

Shawn Rhea | EurekAlert!
Further information:
http://dx.doi.org/10.1038/s41586-020-2359-9

More articles from Physics and Astronomy:

nachricht Spintronics: Researchers show how to make non-magnetic materials magnetic
06.08.2020 | Martin-Luther-Universität Halle-Wittenberg

nachricht Manifestation of quantum distance in flat band materials
05.08.2020 | Institute for Basic Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: ScanCut project completed: laser cutting enables more intricate plug connector designs

Scientists at the Fraunhofer Institute for Laser Technology ILT have come up with a striking new addition to contact stamping technologies in the ERDF research project ScanCut. In collaboration with industry partners from North Rhine-Westphalia, the Aachen-based team of researchers developed a hybrid manufacturing process for the laser cutting of thin-walled metal strips. This new process makes it possible to fabricate even the tiniest details of contact parts in an eco-friendly, high-precision and efficient manner.

Plug connectors are tiny and, at first glance, unremarkable – yet modern vehicles would be unable to function without them. Several thousand plug connectors...

Im Focus: New Strategy Against Osteoporosis

An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.

Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...

Im Focus: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

Rare Earth Elements in Norwegian Fjords?

06.08.2020 | Earth Sciences

Anode material for safe batteries with a long cycle life

06.08.2020 | Power and Electrical Engineering

Turning carbon dioxide into liquid fuel

06.08.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>