Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

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 Käll, 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 Göran 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

Chitosan coated, chemotherapy packed nanoparticles may target cancer stem cells June 30th, 2015

BASF and Fraunhofer IPMS-CNT jointly develop electronic materials June 30th, 2015

Researchers from the UCA, key players in a pioneering study that may explain the origin of several digestive diseases June 30th, 2015

Oxford Instruments’ TritonXL Cryofree dilution refrigerator selected for the Oxford NQIT Quantum Technology Hub project June 30th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Graphene flexes its electronic muscles: Rice-led researchers calculate electrical properties of carbon cones, other shapes June 30th, 2015

X-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th, 2015

Graphene breakthrough as Bosch creates magnetic sensor 100 times more sensitive than silicon equivalent June 28th, 2015

Building a better semiconductor: Research led by Michigan State University could someday lead to the development of new and improved semiconductors June 27th, 2015

Nanomedicine

Chitosan coated, chemotherapy packed nanoparticles may target cancer stem cells June 30th, 2015

Researchers from the UCA, key players in a pioneering study that may explain the origin of several digestive diseases June 30th, 2015

Efforts to Use Smart Nanocarriers to Cure Leukemia Yield Promising Results June 29th, 2015

Chivalrous Knight Does Pro Bono June 27th, 2015

Sensors

Visible Light-Sensitive Photocatalysts Used for Purification of Contaminated Water in Iran June 30th, 2015

Graphene breakthrough as Bosch creates magnetic sensor 100 times more sensitive than silicon equivalent June 28th, 2015

The peaks and valleys of silicon: Team of USC Viterbi School of Engineering Researchers introduce new layered semiconducting materials as silicon alternative June 27th, 2015

Green Chemistry Methods Used in Iran to Produce Zinc Oxide Nanoparticles June 27th, 2015

Discoveries

Chitosan coated, chemotherapy packed nanoparticles may target cancer stem cells June 30th, 2015

Graphene flexes its electronic muscles: Rice-led researchers calculate electrical properties of carbon cones, other shapes June 30th, 2015

Researchers from the UCA, key players in a pioneering study that may explain the origin of several digestive diseases June 30th, 2015

Visible Light-Sensitive Photocatalysts Used for Purification of Contaminated Water in Iran June 30th, 2015

Announcements

BASF and Fraunhofer IPMS-CNT jointly develop electronic materials June 30th, 2015

Graphene flexes its electronic muscles: Rice-led researchers calculate electrical properties of carbon cones, other shapes June 30th, 2015

Researchers from the UCA, key players in a pioneering study that may explain the origin of several digestive diseases June 30th, 2015

Oxford Instruments’ TritonXL Cryofree dilution refrigerator selected for the Oxford NQIT Quantum Technology Hub project June 30th, 2015

Photonics/Optics/Lasers

Making new materials with micro-explosions: ANU media release: Scientists have made exotic new materials by creating laser-induced micro-explosions in silicon, the common computer chip material June 29th, 2015

Opening a new route to photonics Berkeley lab researchers find way to control light in densely packed nanowaveguides June 27th, 2015

The quantum spin Hall effect is a fundamental property of light June 25th, 2015

Laser spectroscopy: A novel microscope for nanosystems June 25th, 2015

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