Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers discover directional and long-lived nanolight in a 2D material

25.10.2018

An international team led by researchers from Monash University (Melbourne, Australia), University of Oviedo (Asturias, Spain), CIC nanoGUNE (San Sebastián, Spain), and Soochow University (Suzhou, China) discover squeezed light ('nanolight') in the nanoscale that propagates only in specific directions along thin slabs of molybdenum trioxide - a natural anisotropic 2D material -. Besides its unique directional character, this nanolight lives for an exceptionally long time, and thus could find applications in signal processing, sensing or heat management at the nanoscale.

Future information and communication technologies will rely on the manipulation of not only electrons but also of light at the nanometer-scale. Squeezing (confining) light to such a small size has been a major goal in nanophotonics for many years. A successful strategy is the use of polaritons, which are electromagnetic waves resulting from the coupling of light and matter.


Illustration of directional nanolight propagating along a thin layer of molybdenum trioxide.

Copyright: Shaojuan Li

Particularly strong light squeezing can be achieved with polaritons at infrared frequencies in 2D materials, such as graphene and hexagonal boron nitride. However, although extraordinary polaritonic properties - such as electrical tuning of graphene polaritons - have been recently achieved with these materials, the polaritons have always been found to propagate along all directions of the material surface, thereby losing energy quite fast, which limits their application potential.

Recently, it was predicted that polaritons can propagate "anisotropically" along the surface of 2D materials, in which the electronic or structural properties are different along different directions. In this case, the velocity and wavelength of the polaritons strongly depend on the direction in which they propagate. This property can lead to highly directional polariton propagation in the form of nanoscale confined rays, which could find future applications in the fields of sensing, heat management or maybe even quantum computing.

Now, an international team led by Qiaoliang Bao (Monash Engineering's Associate Professor, Melbourne, Australia), Pablo Alonso-González (Distinguished researcher at University of Oviedo, Spain) and Rainer Hillenbrand (Ikerbasque Research Professor at CIC nanoGUNE, San Sebastián, Spain) have discovered ultra-confined infrared polaritons that propagate only in specific directions along thin slabs of the natural 2D material molybdenum trioxide (α-MoO3).

"Our findings promise α-MoO3 to become a unique platform for infrared nanophotonics", says Qiaoliang Bao. "It was amazing to discover polaritons on our α-MoO3 thin flakes travelling only along certain directions", says Weiliang Ma, postgraduate-student and co-first-author. "Until now, the directional propagation of polaritons has been observed experimentally only in artificially structured materials, where the ultimate polariton confinement is much more difficult to achieve than in natural materials", adds co-first author Shaojuan Li.

Apart of directional propagation, the study also revealed that the polaritons on α-MoO3 can have an extraordinarily long lifetime. "Light seems to take a nanoscale highway on α-MoO3; it travels along certain directions with almost no obstacles", says Pablo Alonso-González, co-first author of the paper. He adds: "Our measurements show that polaritons on α-MoO3 live up to 20 picoseconds, which is 40 times larger than the best-possible polariton lifetime in high-quality graphene at room temperature".

Because the wavelength of the polaritons is much smaller than that of light, the researchers had to use a special microscope, a so-called near-field optical microscope, to image them. "The establishment of this technique coincided perfectly with the emergence of novel van der Waals materials, enabling the imaging of a variety of unique and even unexpected polaritons during the past years", adds Rainer Hillenbrand.

For a better understanding of the experimental results, the researchers developed a theory that allowed them to extract the relation between the momentum of polaritons in α-MoO3 with their energy. "We have realized that light squeezed in α-MoO3 can become "hyperbolic" making the energy and wave-fronts to propagate in different directions along the surface, which can lead to interesting exotic effects in optics (such as e.g. negative refraction or "superlensing")", says Alexey Nikitin, Ikerbasque Research Associate at Donostia International Physics Center (DIPC), who developed the theory in collaboration with Javier Taboada-Gutiérrez, and Javier Martín-Sánchez, PhD and postdoctoral researchers, respectively at Alonso-Gonzalez´s group.

The current work is just the beginning of a series of studies focused on directional control and manipulation of light with the help of ultra-low-loss polaritons at the nanoscale, which could benefit the development of more efficient nanophotonic devices for optical sensing and signal processing or heat management.

###

Published manuscript:

In-plane anisotropic and ultra-low-loss polaritons in a natural van der Waals crystal Weiliang Ma, Pablo Alonso-González, Shaojuan Li, Alexey Y. Nikitin, Jian Yuan, Javier Martín-Sánchez, Javier Taboada-Gutiérrez, Iban Amenabar, Peining Li, Saül Vélez, Christopher Tollan, Zhigao Dai, Yupeng Zhang, Sharath Sriram, Kourosh Kalantar-Zadeh, Shuit-Tong Lee, Rainer Hillenbrand & Qiaoliang Bao, Nature, DOI: 10.1038/s41586-018-0618-9

Collaborative team/participating parts/involved institutions:

Monash University (Australia); https://www.monash.edu/engineering/qiaoliangbao
University of Oviedo Spain; http://www.uniovi.es
CIC nanoGUNE (Spain); https://www.nanogune.eu/nanooptics
Soochow University (China); http://funsom.suda.edu.cn/funsomen/3015/list.htm
Donostia International Physics Center (DIPC, Spain); http://www.dipc.ehu.es

Acknowledgements

  • Australia: FLEET funding under the Australian Research Council Centres of Excellence program. The research was performed in part at the Melbourne Centre for Nanofabrication (MCN), an Australian National Fabrication Facility (ANFF).
  • China: National Natural Science Foundation of China, Youth 973 program, National Key Research Development Program, Natural Science Foundation of Jiangsu Province, Priority Academic Program Development of Jiangsu, Higher Education Institutions (PAPD) and Collaborative Innovation Center of Suzhou Nano Science and Technology
  • Spain: Ministry of Economy, Industry and Competitiveness, Clarín Programme from the Government of the Principality of Asturias, Maria de Maeztu Units of Excellence Programme.
  • Europe: European Research Council under the Starting grant 715496, "2DNANOPTICA".

ABOUT MONASH UNIVERSITY:

Monash University is a public research university based in Melbourne, Australia. Monash University is one of Australia's leading universities and ranks among the world's top 100. Monash is a member of Australia's Group of Eight, a coalition of Australia's eight leading research Universities, a member of the ASAIHL, and is the only Australian member of the M8 Alliance of Academic Health Centers, Universities and National Academies. http://www.monash.edu

ABOUT UNIVERSITY OF OVIEDO:

The University of Oviedo, located in Oviedo, Asturias, has a teaching and research staff of more than 2000 people in 38 departments, among them are 350 young researchers with expertise ranging from physics, chemistry, life sciences, biology etc., at both a post-graduate and post-doctoral level. http://www.uniovi.es

ABOUT CIC NANOGUNE:

The CIC nanoGUNE Co-operative Research Centre, located in Donostia-San Sebastian, Basque Country, is a research center set up with the mission to perform world-class nanoscience research for the competitive growth of the Basque Country. NanoGUNE is also recognized by the Spanish Research Agency as a "María de Maeztu" Unit of Excellence (2017-2021). http://www.nanogune.eu

ABOUT SOOCHOW UNIVERSITY Soochow University, a Jiangsu provincial key comprehensive university located in Suzhou, Jiangsu, China. The university is part of the national "211 Project" and is a "2011 Plan" university, also one of the top 5% research universities (overall ranking 28 within 704 Chinese universities in 2017) in China. http://www.suda.edu.cn

ABOUT DIPC

The Donostia International Physics Center Foundation (DIPC) (created in 1999) promotes and catalyses the development of basic research in Physics. It presents an international point of reference in the field of the Physics of Materials. http://www.dipc.ehu.es

Media Contact

Irati Kortabitarte
i.kortabitarte@elhuyar.eus

Irati Kortabitarte | EurekAlert!
Further information:
https://www.nature.com/articles/s41586-018-0618-9?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+nature%2Frss%2Fcurrent+%28Nature+-+Issue%29
http://dx.doi.org/10.1038/s41586-018-0618-9

More articles from Materials Sciences:

nachricht Scientists develop low-cost energy-efficient materials
24.04.2019 | National University of Science and Technology MISIS

nachricht Modified 'white graphene' for eco-friendly energy
23.04.2019 | Tomsk Polytechnic University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Energy-saving new LED phosphor

The human eye is particularly sensitive to green, but less sensitive to blue and red. Chemists led by Hubert Huppertz at the University of Innsbruck have now developed a new red phosphor whose light is well perceived by the eye. This increases the light yield of white LEDs by around one sixth, which can significantly improve the energy efficiency of lighting systems.

Light emitting diodes or LEDs are only able to produce light of a certain colour. However, white light can be created using different colour mixing processes.

Im Focus: Quantum gas turns supersolid

Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.

Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...

Im Focus: Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter

  • Coolest and smallest star to produce a superflare found
  • Star is a tenth of the radius of our Sun
  • Researchers led by University of Warwick could only see...

Im Focus: Quantum simulation more stable than expected

A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.

Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...

Im Focus: Largest, fastest array of microscopic 'traffic cops' for optical communications

The technology could revolutionize how information travels through data centers and artificial intelligence networks

Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

Proteins stand up to nerve cell regression

24.04.2019 | Life Sciences

New sensor detects rare metals used in smartphones

24.04.2019 | Life Sciences

Controlling instabilities gives closer look at chemistry from hypersonic vehicles

24.04.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>