Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

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

News and information

Iranian Experts Clean Uranium-Contaminated Water by Nano-Particles November 23rd, 2014

Novel Method Found for Connection of Metallic Alloys to Polymers November 23rd, 2014

New research project supports internationalisation in nano-research: Launch of new “Baltic Sea Network” November 22nd, 2014

3rd Iran-Proposed Nano Standard Approved by International Standard Organization November 22nd, 2014

Chemistry

UO-industry collaboration points to improved nanomaterials: University of Oregon microscope puts spotlight on the surface structure of quantum dots for designing new solar devices November 20th, 2014

Silver Nanoparticles Produced in Iran from Forest Plants Extract November 20th, 2014

Imaging

Leica Microsystems Presents Universal Hybrid Detector for Single Molecule Detection and Imaging at SfN and ASCB: Leica HyD SMD - the Optimal Detector for Precise and Reliable SMD data November 20th, 2014

NRL Scientists Discover Novel Metamaterial Properties within Hexagonal Boron Nitride November 20th, 2014

Spectral Surface Mapping with Microscopic Resolution: CRAIC Technologies introduces Spectral Surface Mapping™ (S2M™) software November 18th, 2014

Discoveries

Iranian Experts Clean Uranium-Contaminated Water by Nano-Particles November 23rd, 2014

Novel Method Found for Connection of Metallic Alloys to Polymers November 23rd, 2014

NMTI announces breakthrough solutions for HAMR nanoantenna for next-generation ultra-high density magnetic storage November 21st, 2014

Nano Sorbents Able to Remove Pollutions Caused by Oil Derivatives November 20th, 2014

Announcements

Iranian Experts Clean Uranium-Contaminated Water by Nano-Particles November 23rd, 2014

Novel Method Found for Connection of Metallic Alloys to Polymers November 23rd, 2014

New research project supports internationalisation in nano-research: Launch of new “Baltic Sea Network” November 22nd, 2014

3rd Iran-Proposed Nano Standard Approved by International Standard Organization November 22nd, 2014

Photonics/Optics/Lasers

NRL Scientists Discover Novel Metamaterial Properties within Hexagonal Boron Nitride November 20th, 2014

Penn engineers efficiently 'mix' light at the nanoscale November 17th, 2014

'Direct writing' of diamond patterns from graphite a potential technological leap November 5th, 2014

Outsmarting Thermodynamics in Self-assembly of Nanostructures: Berkeley Lab reports method for symmetry-breaking in feedback-driven self-assembly of optical metamaterials November 4th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE