Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Metal nanoparticles shine with customizable color: A new way to create and control color has implications for display screens and security tags

Abstract:
Engineers at Harvard have demonstrated a new kind of tunable color filter that uses optical nanoantennas to obtain precise control of color output.

Metal nanoparticles shine with customizable color: A new way to create and control color has implications for display screens and security tags

Cambridge, MA | Posted on February 23rd, 2012

Whereas a conventional color filter can only produce one fixed color, a single active filter under exposure to different types of light can produce a range of colors.

The advance has the potential for application in televisions and biological imaging, and could even be used to create invisible security tags to mark currency. The findings appear in the February issue of Nano Letters.

Kenneth Crozier, Associate Professor of Electrical Engineering at the Harvard School of Engineering and Applied Sciences (SEAS), and colleagues have engineered the size and shape of metal nanoparticles so that the color they appear strongly depends on the polarization of the light illuminating them. The nanoparticles can be regarded as antennas—similar to antennas used for wireless communications—but much smaller in scale and operating at visible frequencies.

"With the advances in nanotechnology, we can precisely control the shape of the optical nanoantennas, so we can tune them to react differently with light of different colors and different polarizations," said co-author Tal Ellenbogen, a postdoctoral fellow at SEAS. "By doing so, we designed a new sort of controllable color filter."

Conventional RGB filters used to create color in today's televisions and monitors have one fixed output color (red, green, or blue) and create a broader palette of hues through blending. By contrast, each pixel of the nanoantenna-based filters is dynamic and able to produce different colors when the polarization is changed.

The researchers dubbed these filters "chromatic plasmonic polarizers" as they can create a pixel with a uniform color or complex patterns with colors varying as a function of position.

To demonstrate the technology's capabilities, the acronym LSP (short for localized
surface plasmon) was created. With unpolarized light or with light which is polarized at 45 degrees, the letters are invisible (gray on gray). In polarized light at 90 degrees, the letters appear vibrant yellow with a blue background, and at 0 degrees the color scheme is reversed. By rotating the polarization of the incident light, the letters then change color, moving from yellow to blue.

"What is somewhat unusual about this work is that we have a color filter with a response that depends on polarization," says Crozier.

The researchers envision several kinds of applications: using the color functionality to present different colors in a display or camera, showing polarization effects in tissue for biomedical imaging, and integrating the technology into labels or paper to generate security tags that could mark money and other objects.

Seeing the color effects from current fabricated samples requires magnification, but large-scale nanoprinting techniques could be used to generate samples big enough to be seen with the naked eye. To build a television, for example, using the nanoantennas would require a great deal of advanced engineering, but Crozier and Ellenbogen say it is absolutely feasible.

Crozier credits the latest advance, in part, to taking a biological approach to the problem of color generation. Ellenbogen, who is, ironically, colorblind, had previously studied computational models of the visual cortex and brought such knowledge to the lab.

"The chromatic plasmonic polarizers combine two structures, each with a different spectral response, and the human eye can see the mixing of these two spectral responses as color," said Crozier.

"We would normally ask what is the response in terms of the spectrum, rather than what is the response in terms of the eye," added Ellenbogen.

The researchers have filed a provisional patent for their work.

Kwanyong Seo, a postdoctoral fellow in electrical engineering at SEAS, also contributed to the research. The work was supported by the Center for Excitonics, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences; and Zena Technologies. In addition, the research team acknowledges the Center for Nanoscale Systems at Harvard for fabrication work.

####

For more information, please click here

Contacts:
Caroline Perry

617-496-1351

Copyright © Harvard University

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 News Press

News and information

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Deep Space Industries and SFL selected to provide satellites for HawkEye 360’s Pathfinder mission: The privately-funded space-based global wireless signal monitoring system will be developed by Deep Space Industries and UTIAS Space Flight Laboratory May 26th, 2016

Display technology/LEDs/SS Lighting/OLEDs

Nanotubes are beacons in cancer-imaging technique: Rice University researchers use spectral triangulation to pinpoint location of tumors May 21st, 2016

This 'nanocavity' may improve ultrathin solar panels, video cameras and more May 16th, 2016

New research shows how silver could be the key to gold-standard flexible gadgets: Silver nanowires are an ideal material for current and future flexible touch-screen technologies May 13th, 2016

First single-enzyme method to produce quantum dots revealed: Biological manufacturing process, pioneered by three Lehigh University engineers, produces equivalent quantum dots to those made chemically--but in a much greener, cheaper way May 9th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

Law enforcement/Anti-Counterfeiting/Security/Loss prevention

A better hologram for fraud protection and wearable optics: Nanotechnology improves holographic capabilities by encoding light polarization May 16th, 2016

Discoveries

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

PETA science group publishes a review on pulmonary effects of nanomaterials: Archives of Toxicology publishes a review of scientific studies on fibrotic potential of nanomaterials May 26th, 2016

Harnessing solar and wind energy in one device could power the 'Internet of Things' May 26th, 2016

Announcements

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Doubling down on Schrödinger's cat May 27th, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Deep Space Industries and SFL selected to provide satellites for HawkEye 360’s Pathfinder mission: The privately-funded space-based global wireless signal monitoring system will be developed by Deep Space Industries and UTIAS Space Flight Laboratory May 26th, 2016

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







Car Brands
Buy website traffic