Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Bimetallic nanoantenna separates colours of light

The nanoantenna acts as a router for red and blue light, due to the nanoparticles of gold and silver having different optical properties. Image: Timur Shegai
The nanoantenna acts as a router for red and blue light, due to the nanoparticles of gold and silver having different optical properties.

Image: Timur Shegai

Abstract:
Researchers at Chalmers University of Technology have built a very simple nanoantenna that directs red and blue colours in opposite directions, even though the antenna is smaller than the wavelength of light. The findings - published in the online journal Nature Communications this week - can lead to optical nanosensors being able to detect very low concentrations of gases or biomolecules.

Bimetallic nanoantenna separates colours of light

Gothenburg, Sweden | Posted on September 24th, 2011

A structure that is smaller than the wavelength of visible light (390-770 nanometers) should not really be able to scatter light. But that is exactly what the new nanoantenna does. The trick employed by the Chalmers researchers is to build an antenna with an asymmetric material composition, creating optical phase shifts.

The antenna consists of two nanoparticles about 20 nanometers apart on a glass surface, one of silver and one of gold. Experiments show that the antenna scatters visible light so that red and blue colours are directed in opposite directions.

"The explanation for this exotic phenomenon is optical phase shifts," says Timur Shegai, one of the researchers behind the discovery. "The reason is that nanoparticles of gold and silver have different optical properties, in particular different plasmon resonances. Plasmon resonance means that the free electrons of the nanoparticles oscillate strongly in pace with the frequency of the light, which in turn affects the light propagation even though the antenna is so small."

The method used by the Chalmers researchers to control the light by using asymmetric material composition - such as silver and gold - is completely new. It is easy to build this kind of nanoantenna; the researchers have shown that the antennas can be fabricated densely over large areas using cheap colloidal lithography.

The research field of nanoplasmonics is a rapidly growing area, and concerns controlling how visible light behaves at the nanoscale using a variety of metal nanostructures. Scientists now have a whole new parameter - asymmetric material composition - to explore in order to control the light.

Nanoplasmonics can be applied in a variety of areas, says Mikael Kšll, professor in the research group at Chalmers.

"One example is optical sensors, where you can use plasmons to build sensors which are so sensitive that they can detect much lower concentrations of toxins or signalling substances than is possible today. This may involve the detection of single molecules in a sample, for example, to diagnose diseases at an early stage, which facilitates quick initiation of treatment."

The results were presented at an international conference on optical nanosensors at Chalmers this week. Chalmers is one of the leading universities in nanoplasmonic biosensors, and 130 scientists from around the world are attending the conference.

The research has received financial support from the Swedish Foundation for Strategic Research, the Swedish Research Council and the GŲran Gustafsson Foundation.

####

For more information, please click here

Contacts:
Christian Borg

Copyright © AlphaGalileo

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Novel 'converter' heralds breakthrough in ultra-fast data processing at nanoscale: Invention bagged four patents and could potentially make microprocessor chips work 1,000 times faster October 20th, 2017

Strange but true: turning a material upside down can sometimes make it softer October 20th, 2017

Leti Coordinating Project to Develop Innovative Drivetrains for 3rd-generation Electric Vehicles: CEA Techís Contribution Includes Litenís Knowhow in Magnetic Materials and Simulation And Letiís Expertise in Wide-bandgap Semiconductors October 20th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Leti Coordinating Project to Develop Innovative Drivetrains for 3rd-generation Electric Vehicles: CEA Techís Contribution Includes Litenís Knowhow in Magnetic Materials and Simulation And Letiís Expertise in Wide-bandgap Semiconductors October 20th, 2017

Bringing the atomic world into full color: Researchers turn atomic force microscope measurements into color images October 19th, 2017

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Nanomedicine

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Arrowhead Pharmaceuticals to Present Preclinical Data on ARO-AAT at The Liver Meeting(R) October 10th, 2017

Arrowhead to Present at Chardan Gene Therapy Conference October 3rd, 2017

'CRISPR-Gold' fixes Duchenne muscular dystrophy mutation in mice October 3rd, 2017

Sensors

MIPT scientists revisit optical constants of ultrathin gold films October 20th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Single Ďsolitonsí promising for optical technologies October 9th, 2017

Two dimensional materials: Advanced molybdenum selenide near infrared phototransistors September 27th, 2017

Discoveries

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Novel 'converter' heralds breakthrough in ultra-fast data processing at nanoscale: Invention bagged four patents and could potentially make microprocessor chips work 1,000 times faster October 20th, 2017

Strange but true: turning a material upside down can sometimes make it softer October 20th, 2017

MIPT scientists revisit optical constants of ultrathin gold films October 20th, 2017

Announcements

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Novel 'converter' heralds breakthrough in ultra-fast data processing at nanoscale: Invention bagged four patents and could potentially make microprocessor chips work 1,000 times faster October 20th, 2017

Strange but true: turning a material upside down can sometimes make it softer October 20th, 2017

Leti Coordinating Project to Develop Innovative Drivetrains for 3rd-generation Electric Vehicles: CEA Techís Contribution Includes Litenís Knowhow in Magnetic Materials and Simulation And Letiís Expertise in Wide-bandgap Semiconductors October 20th, 2017

Photonics/Optics/Lasers

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Novel 'converter' heralds breakthrough in ultra-fast data processing at nanoscale: Invention bagged four patents and could potentially make microprocessor chips work 1,000 times faster October 20th, 2017

MIPT scientists revisit optical constants of ultrathin gold films October 20th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project