Featured Research

from universities, journals, and other organizations

Building 'invisible' materials with light

Date:
July 28, 2014
Source:
University of Cambridge
Summary:
A new technique which uses light like a needle to thread long chains of particles could help bring sci-fi concepts such as cloaking devices one step closer to reality.

This image depicts an efficient route to manufacturing nanomaterials with light through plasmon-induced laser-threading of gold nanoparticle strings.
Credit: Ventsislav Valev

A new method of building materials using light, developed by researchers at the University of Cambridge, could one day enable technologies that are often considered the realm of science fiction, such as invisibility cloaks and cloaking devices.

Although cloaked starships won't be a reality for quite some time, the technique which researchers have developed for constructing materials with building blocks a few billionths of a metre across can be used to control the way that light flies through them, and works on large chunks all at once. Details are published today (28 July) in the journal Nature Communications.

The key to any sort of 'invisibility' effect lies in the way light interacts with a material. When light hits a surface, it is either absorbed or reflected, which is what enables us to see objects. However, by engineering materials at the nanoscale, it is possible to produce 'metamaterials': materials which can control the way in which light interacts with them. Light reflected by a metamaterial is refracted in the 'wrong' way, potentially rendering objects invisible, or making them appear as something else.

Metamaterials have a wide range of potential applications, including sensing and improving military stealth technology. However, before cloaking devices can become reality on a larger scale, researchers must determine how to make the right materials at the nanoscale, and using light is now shown to be an enormous help in such nano-construction.

The technique developed by the Cambridge team involves using unfocused laser light as billions of needles, stitching gold nanoparticles together into long strings, directly in water for the first time. These strings can then be stacked into layers one on top of the other, similar to Lego bricks. The method makes it possible to produce materials in much higher quantities than can be made through current techniques.

In order to make the strings, the researchers first used barrel-shaped molecules called cucurbiturils (CBs). The CBs act like miniature spacers, enabling a very high degree of control over the spacing between the nanoparticles, locking them in place.

In order to connect them electrically, the researchers needed to build a bridge between the nanoparticles. Conventional welding techniques would not be effective, as they cause the particles to melt. "It's about finding a way to control that bridge between the nanoparticles," said Dr Ventsislav Valev of the University's Cavendish Laboratory, one of the authors of the paper. "Joining a few nanoparticles together is fine, but scaling that up is challenging."

The key to controlling the bridges lies in the cucurbiturils: the precise spacing between the nanoparticles allows much more control over the process. When the laser is focused on the strings of particles in their CB scaffolds, it produces plasmons: ripples of electrons at the surfaces of conducting metals. These skipping electrons concentrate the light energy on atoms at the surface and join them to form bridges between the nanoparticles. Using ultrafast lasers results in billions of these bridges forming in rapid succession, threading the nanoparticles into long strings, which can be monitored in real time.

"We have controlled the dimensions in a way that hasn't been possible before," said Dr Valev, who worked with researchers from the Department of Chemistry and the Department of Materials Science & Metallurgy on the project. "This level of control opens up a wide range of potential practical applications."


Story Source:

The above story is based on materials provided by University of Cambridge. The original story is licensed under a Creative Commons Licence. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lars O. Herrmann, Ventsislav K. Valev, Christos Tserkezis, Jonathan S. Barnard, Setu Kasera, Oren A. Scherman, Javier Aizpurua, Jeremy J. Baumberg. Threading plasmonic nanoparticle strings with light. Nature Communications, 2014; 5 DOI: 10.1038/ncomms5568

Cite This Page:

University of Cambridge. "Building 'invisible' materials with light." ScienceDaily. ScienceDaily, 28 July 2014. <www.sciencedaily.com/releases/2014/07/140728080742.htm>.
University of Cambridge. (2014, July 28). Building 'invisible' materials with light. ScienceDaily. Retrieved September 14, 2014 from www.sciencedaily.com/releases/2014/07/140728080742.htm
University of Cambridge. "Building 'invisible' materials with light." ScienceDaily. www.sciencedaily.com/releases/2014/07/140728080742.htm (accessed September 14, 2014).

Share This



More Matter & Energy News

Sunday, September 14, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Frustration As Drone Industry Outpaces Regulation In U.S.

Frustration As Drone Industry Outpaces Regulation In U.S.

Newsy (Sep. 14, 2014) U.S. firms worry they’re falling behind in the marketplace as the FAA considers how to regulate commercial drones. Video provided by Newsy
Powered by NewsLook.com
Scientists Have Captured The Sound Of An Atom

Scientists Have Captured The Sound Of An Atom

Newsy (Sep. 12, 2014) Scientists have captured the sound of a single atom by measuring its vibrations. We can't hear it, but it's reportedly the faintest sound possible. Video provided by Newsy
Powered by NewsLook.com
Solar Flare Surges Off Sun

Solar Flare Surges Off Sun

Reuters - US Online Video (Sep. 11, 2014) NASA captures video of a significant flare surging off the sun. Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Soccer Players' Feet to Generate Electricity

Soccer Players' Feet to Generate Electricity

AP (Sep. 11, 2014) A new energy-generating soccer field was inaugurated in Brazil. The field is built on energy-capturing tiles, allowing players to generate electricity as they run and compete. (Sept. 11) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins