Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

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

Imaging

FEI Technology Award of the German Neuroscience Society Goes to Benjamin Judkewitz of the University of Berlin: Bi-annual award honors excellence in brain research during the German Neuroscience Society’s Annual Meeting, held 18-21 March 2015 March 26th, 2015

News and information

Hong Kong Investors Bullish on Dais Analytic Invest $5.75M, Provide $60M Contract, and Create New Joint Venture Company March 26th, 2015

Industrial Nanotech, Inc. Announces Next Large Order from the Oil and Gas Industry March 26th, 2015

Quantum compute this -- WSU mathematicians build code to take on toughest of cyber attacks: Revamped knapsack code offers online security for the future March 26th, 2015

Thousands of atoms entangled with a single photon: Result could make atomic clocks more accurate March 26th, 2015

Chemistry

First proof of isolated attosecond pulse generation at the carbon K-edge March 20th, 2015

Click! That's how modern chemistry bonds nanoparticles to a substrate March 19th, 2015

Chromium-Centered Cycloparaphenylene Rings as New Tools for Making Functionalized Nanocarbons February 24th, 2015

Stretch and relax! -- Losing 1 electron switches magnetism on in dichromium February 23rd, 2015

Discoveries

Quantum compute this -- WSU mathematicians build code to take on toughest of cyber attacks: Revamped knapsack code offers online security for the future March 26th, 2015

Thousands of atoms entangled with a single photon: Result could make atomic clocks more accurate March 26th, 2015

Square ice filling for a graphene sandwich March 26th, 2015

Application of Graphene Oxide in Body Implants in Iran March 26th, 2015

Announcements

Industrial Nanotech, Inc. Announces Next Large Order from the Oil and Gas Industry March 26th, 2015

Quantum compute this -- WSU mathematicians build code to take on toughest of cyber attacks: Revamped knapsack code offers online security for the future March 26th, 2015

Thousands of atoms entangled with a single photon: Result could make atomic clocks more accurate March 26th, 2015

Square ice filling for a graphene sandwich March 26th, 2015

Photonics/Optics/Lasers

Bar-Ilan U. researchers identify 'tipping point' between quantum and classical worlds: Study sheds new light on 'spooky' quantum optics March 24th, 2015

UW scientists build a nanolaser using a single atomic sheet March 24th, 2015

Building shape inspires new material discovery March 24th, 2015

EEE Photonics Society’s Fourth Annual Optical Interconnects Conference Seeks to Bring Together the Latest Advanced Optical Interconnect Technologies, Systems & Architectures for the Next Generation of Supercomputers & Datacenters March 23rd, 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







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE