Featured Research

from universities, journals, and other organizations

New nanoscale imaging method finds application in plasmonics

Date:
July 16, 2013
Source:
National Institute of Standards and Technology (NIST)
Summary:
Researchers have shown how to make nanoscale measurements of critical properties of plasmonic nanomaterials, the specially engineered nanostructures that modify the interaction of light and matter for a variety of applications including sensors, cloaking (invisibility), photovoltaics and therapeutics.

Infrared laser light (purple) from below a sample (blue) excites ring shaped nanoscale plasmonic resonator structures (gold). Hot spots (white) form in the rings' gaps. In these hot spots, infrared absorption is enhanced, allowing for more sensitive chemical recognition. A scanning AFM tip detects the expansion of the underlying material in response to absorption of infrared light.
Credit: NIST

Researchers from the National Institute of Standards and Technology (NIST) and the University of Maryland have shown how to make nanoscale measurements of critical properties of plasmonic nanomaterials -- the specially engineered nanostructures that modify the interaction of light and matter for a variety of applications, including sensors, cloaking (invisibility), photovoltaics and therapeutics.

Their technique is one of the few that allows researchers to make actual physical measurements of these materials at the nanoscale without affecting the nanomaterial's function.

Plasmonic nanomaterials contain specially engineered conducting nanoscale structures that can enhance the interaction between light and an adjacent material, and the shape and size of such nanostructures can be adjusted to tune these interactions. Theoretical calculations are frequently used to understand and predict the optical properties of plasmonic nanomaterials, but few experimental techniques are available to study them in detail. Researchers need to be able to measure the optical properties of individual structures and how each interacts with surrounding materials directly in a way that doesn't affect how the structure functions.

"We want to maximize the sensitivity of these resonator arrays and study their properties," says lead researcher Andrea Centrone. "In order to do that, we needed an experimental technique that we could use to verify theory and to understand the influence of nanofabrication defects that are typically found in real samples. Our technique has the advantage of being extremely sensitive spatially and chemically, and the results are straightforward to interpret."

The research team turned to photothermal induced resonance (PTIR), an emerging chemically specific materials analysis technique, and showed it can be used to image the response of plasmonic nanomaterials excited by infrared (IR) light with nanometer-scale resolution.

The team used PTIR to image the absorbed energy in ring-shaped plasmonic resonators. The nanoscale resonators focus the incoming IR light within the rings' gaps to create "hot spots" where the light absorption is enhanced, which makes for more sensitive chemical identification. For the first time, the researchers precisely quantified the absorption in the hot spots and showed that for the samples under investigation, it is approximately 30 times greater than areas away from the resonators.

The researchers also showed that plasmonic materials can be used to increase the sensitivity of IR and PTIR spectroscopy for chemical analysis by enhancing the local light intensity, and thereby, the spectroscopic signal.

Their work further demonstrated the versatility of PTIR as a measurement tool that allows simultaneous measurement of a nanomaterial's shape, size, and chemical composition -- the three characteristics that determine a nanomaterial's properties. Unlike many other methods for probing materials at the nanoscale, PTIR doesn't interfere with the material under investigation; it doesn't require the researcher to have prior knowledge about the material's optical properties or geometry; and it returns data that is more easily interpretable than other techniques that require separating the response of the sample from response of the probe.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. Basudev Lahiri, Glenn Holland, Vladimir Aksyuk, Andrea Centrone. Nanoscale Imaging of Plasmonic Hot Spots and Dark Modes with the Photothermal-Induced Resonance Technique. Nano Letters, 2013; 13 (7): 3218 DOI: 10.1021/nl401284m

Cite This Page:

National Institute of Standards and Technology (NIST). "New nanoscale imaging method finds application in plasmonics." ScienceDaily. ScienceDaily, 16 July 2013. <www.sciencedaily.com/releases/2013/07/130716132236.htm>.
National Institute of Standards and Technology (NIST). (2013, July 16). New nanoscale imaging method finds application in plasmonics. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2013/07/130716132236.htm
National Institute of Standards and Technology (NIST). "New nanoscale imaging method finds application in plasmonics." ScienceDaily. www.sciencedaily.com/releases/2013/07/130716132236.htm (accessed October 21, 2014).

Share This



More Matter & Energy News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gulfstream G500, G600 Unveiling

Gulfstream G500, G600 Unveiling

Flying (Oct. 20, 2014) Watch Gulfstream's public launch of the G500 and G600 at their headquarters in Savannah, Ga., along with a surprise unveiling of the G500, which taxied up under its own power. Video provided by Flying
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
What We Know About Microsoft's Rumored Smartwatch

What We Know About Microsoft's Rumored Smartwatch

Newsy (Oct. 20, 2014) Microsoft will reportedly release a smartwatch that works across different mobile platforms, has a two-day battery life and tracks heart rate. Video provided by Newsy
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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