Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Superlens squeezes light into nanospace

16.06.2020

Plasmon nanojet: Physicists implement efficient mechanism for subwavelength focusing of plasmons

Russian and Danish researchers have made a first-ever experimental observation of a plasmon nanojet. This physical phenomenon enables nanoscale focusing of light and, theoretically, allows engineers to bypass one of the fundamental limitations of the ordinary converging lens.


An artist's conception of the superlens compressing a laser beam into more manageable, lower-wavelength electromagnetic oscillations. Scroll down for a more accurate graphic representation

Credit: Daria Sokol/MIPT Press Office

Tight compression of light waves is necessary to use them as signal carriers in compact devices that would work much faster than today's electronics. The study comes out in the June 15 issue of Optics Letters.

Before laser pointers became available, the amorous heroes of romance novels had to make do with small rocks they would throw into a beloved's window to indicate their presence. Among the numerous drawbacks of rocks as signal carriers is their mass, which means sending a message requires an effort and time.

While the electron does not weigh as much as a rock, it still cannot be put in motion instantaneously. If we could replace the electrons in microcircuits with photons -- the massless particles of light -- the resulting devices would operate much faster.

What prevents engineers from abandoning electronic chips in favor of their photonic analogues is the need for miniaturization. With today's technology, such optical devices would have an enormous size. To make them smaller, engineers require a way to control photons on such a small scale that the light wave itself has to be localized, squeezed into a minimum space.

Ideally, the light needs to be focused into a spot smaller than 50% of the original wavelength. While this feat is impossible in the classical optics due to what's known as the diffraction limit, modern research has already found several ways around it. And the newly observed plasmon nanojet is likely to become one of them.

A team of Russian and Danish physicists has created a focusing component, or nanolens, capable of converting light into electromagnetic waves of a special kind, compressing it to 60% of the initial radiation wavelength.

This new contraption is made up of a square piece of dielectric material 5 by 5 micrometers in size and 0.25 micrometers thick. Shown in figure 1, the square particle lies on a thin 0.1-micrometer gold film, next to an etched grating that diffracts light.

Illuminating the grating in the gold film with a laser generates excitations known as surface plasmon polaritons, which travel along the metal's surface. These SPPs are essentially two kinds of waves coupled to each other and propagating together.

First, there's the collective oscillation of electrons in gold -- the plasmon part -- and then there's also a surface light wave called a polariton. The point of converting light to SPPs is that there are ways to focus them to a greater extent than the initial laser pulse.

"One of the mechanisms that enable subwavelength focusing relies on the plasmon nanojet, a phenomenon we have observed in an experiment for the first time," said the paper's lead author, Professor Igor Minin of Tomsk Polytechnic University.

The scientific explanation of why waves undergo compression in the superlens is as follows. "Using computer simulations, we figured out the appropriate dimensions of the dielectric particle and the diffraction grid in the gold film. When these parameters are right, SPPs have different phase velocities at different points in the particle.

This causes the wavefront to bend, creating a vortex in the particle and therefore a region dense with SPPs behind it, which we call a plasmon nanojet," said study co-author Dmitry Ponomarev, a leading researcher at the MIPT Laboratory of 2D Materials and Nanodevices and the deputy director of Mokerov Institute of Ultra High Frequency Semiconductor Electronics of the Russian Academy of Sciences.

The study has demonstrated a new and efficient mechanism for strongly localizing radiation and manipulating it on the nanoscale, which is a prerequisite for densely packing optical components in photonic and plasmonic devices that would operate much faster than conventional electronics.

The head of the MIPT Center for Photonics and 2D Materials, Valentyn Volkov, who co-authored the study, added: "The experimental observation of plasmon nanojets has been made possible by a concerted effort on the part of our center's researchers and the colleagues in Moscow, Tomsk, and Copenhagen.

This collaboration is not over, and we are planning to show other exciting effects that have to do with the formation, propagation, and application of plasmon nanojets."

Media Contact

Varvara Bogomolova
bogomolova@phystech.edu
891-614-74496

 @phystech_en

https://mipt.ru/english/ 

Varvara Bogomolova | EurekAlert!
Further information:
https://mipt.ru/english/news/new_supelens_has_potential_to_circumvent_classical_optics_laws
http://dx.doi.org/10.1364/OL.391861

More articles from Physics and Astronomy:

nachricht Excitation of robust materials
07.07.2020 | Christian-Albrechts-Universität zu Kiel

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

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: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

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

07.07.2020 | 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

 
Latest News

Nutrients in microalgae: an environmentally friendly alternative to fish

07.07.2020 | Health and Medicine

Mobile measuring instruments: Caught in flight

07.07.2020 | Power and Electrical Engineering

Exploring Rapid Changes in the Arctic Ecosystem

07.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>