Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > ‘Loops of light’ promising for optical detection of individual molecules

Abstract:
KU Leuven researcher Ventsislav Valev and an international team of colleagues have developed a new method for manipulating light at the nanoscale in order to optically detect single molecules. By shining circularly polarised light on a gold, square-ring shaped nanostructure, the researchers were able to ‘activate' the entire surface of the nanostructure, thereby significantly increasing the opportunity for interaction with molecules. The method has a broad range of potential applications in nanoscale photochemistry and could assist in the advancement of technologies for visualising single molecules and multiple-molecule interactions.

‘Loops of light’ promising for optical detection of individual molecules

Leuven, Belgium | Posted on July 19th, 2012

Nanotechnology researchers around the world are exploring ways to optically detect single molecules, but progress can be hindered by the fact that single molecules have extremely weak optical responses. Thus far, scientists have developed a way to use metal nanostructures to focus light into tiny spots called ‘hotspots'. The hotspots excite electrons on the surface of the nanostructure, causing them to oscillate coherently. When shone on a molecule, and with the help of these oscillating electrons, the focused light can increase a molecule's optical signal to 100 billion times its normal strength. This signal can then be detected with an optical microscope.

But there are two limitations to the current method: hotspots can become too hot, and they are just spots. That is, the heat from hotspots can melt the nanostructures, thus destroying their ability to channel light effectively, and hotspots produce only a very small cross-section in which interaction with molecules can take place. Additionally, for a single molecule to become detectable, it needs to find the hotspot.

Loops of light

In order to overcome these limitations, Dr. Valev and his colleagues sought out to nanoengineer larger spots. They began by shining circularly polarised light rather than linearly polarised light on the nanostructures and found that this could increase the useful area of these nanostructures. More importantly, when shone on square-ring shaped gold nanostructures, the scientists observed that theentire surface of the nanostructures was successfully activated.

Dr. Valev explains: "Essentially, light is constituted of electric and magnetic fields moving through space. While with linearly polarised light, the fields move in a linear, forward direction, with circularly polarised light, they rotate in a spiral-like motion." The circularly polarised light imparts a sense of rotation on the electron density in ring-shaped gold nanostructures, thus trapping the light in the rings and forming ‘loops of light'. The loops of light cause excited electrons to oscillate coherently on the full surface of the square-ringed nanostructures - rather than in a few concentrated hotspots. This increases the opportunity for interaction with molecules: "The trick is to try to activate the whole surface of the nanostructure so that whenever a molecule attaches, we will be able to see it," says Dr. Valev. "That is precisely what we did."

The method has a broad range of potential applications in nanoscale photochemistry and could assist in the advancement of technologies for visualising single molecules and multiple-molecule interactions. The findings were published in the scientific journal Advanced Materials.

Full bibliographic information

Valev, V. K., De Clercq, B., Biris, C. G., Zheng, X., Vandendriessche, S., Hojeij, M., Denkova, D., Jeyaram, Y., Panoiu, N. C., Ekinci, Y., Silhanek, A. V., Volskiy, V., Vandenbosch, G. A. E., Ameloot, M., Moshchalkov, V. V. and Verbiest, T. (2012), Distributing the Optical Near-Field for Efficient Field-Enhancements in Nanostructures. Advanced Materials doi: 10.1002/adma.201201151

####

For more information, please click here

Contacts:
Ventsislav Valev
Molecular Imaging and Photonics
KU Leuven
+32 16 3 27622

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 Links

The full text of the paper “Distributing the optical near-field for efficient field-enhancements in nanostructures” is available on the website of Advanced Materials:

Related News Press

Chemistry

Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025

News and information

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Imaging

New material to make next generation of electronics faster and more efficient With the increase of new technology and artificial intelligence, the demand for efficient and powerful semiconductors continues to grow November 8th, 2024

Turning up the signal November 8th, 2024

New discovery aims to improve the design of microelectronic devices September 13th, 2024

Quantum researchers cause controlled ‘wobble’ in the nucleus of a single atom September 13th, 2024

Discoveries

Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025

Cambridge chemists discover simple way to build bigger molecules – one carbon at a time June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Announcements

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Photonics/Optics/Lasers

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Following the folds – with quantum technology: The connection between a crumpled sheet of paper and quantum technology: A research team at the EPFL in Lausanne (Switzerland) and the University of Konstanz (Germany) uses topology in microwave photonics to make improved systems of May 16th, 2025

Programmable electron-induced color router array May 14th, 2025

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




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project