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 FAST detects neutral hydrogen emission from extragalactic galaxies for the first time
02.07.2020 | Chinese Academy of Sciences Headquarters

nachricht First exposed planetary core discovered
01.07.2020 | Universität Bern

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: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

Im Focus: AI monitoring of laser welding processes - X-ray vision and eavesdropping ensure quality

With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.

Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

 
Latest News

Coupled hair cells in the inner ear – „Together we are strong!“

06.07.2020 | Health and Medicine

Innovations for sustainability in a post-pandemic future

06.07.2020 | Social Sciences

Carbon-loving materials designed to reduce industrial emissions

06.07.2020 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>