Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Making a tiny rainbow

29.01.2015

By varying the size and spacing of aluminum nanodisks, researchers generate images that contain over 300 colors and are not much wider than a human hair

A scheme for greatly increasing the number of colors that can be produced by arrays of tiny aluminum nanodisks has been demonstrated by A*STAR scientists1.


Three strategies for producing colors of pixels containing four aluminum nanodisks. Row 1: varying the nanodisk diameter (d) gives 15 colors. Row 2: Varying both the spacing (s) and diameter (d) of the nanodisks gives over 300 colors. Row 3: Varying the diameters (d1 and d2) of the two pairs of diametrically opposite nanodisks gives over 100 colors.

Modified, with permission, from Ref. 1 © 2014 American Chemical Society

Conventional pigments produce colors by selectively absorbing light of different wavelengths — for example, red ink appears red because it absorbs strongly in the blue and green spectral regions. A similar effect can be realized at a much smaller scale by using arrays of metallic nanostructures, since light of certain wavelengths excites collective oscillations of free electrons, known as plasmon resonances, in such structures.

An advantage of using metal nanostructures rather than inks is that it is possible to enhance the resolution of color images by a hundred fold. This enhanced resolution, at the diffraction limit of light, is critical for data storage, digital imaging and security applications. Aluminum — because of its low cost and good stability — is a particularly attractive material to use.

Joel Yang and Shawn Tan at the A*STAR Institute of Materials Research and Engineering and co-workers used an electron beam to form arrays of approximately 100-nanometer-tall pillars. They then deposited a thin aluminum layer on top of the pillars and in the gaps between them. In these arrays, each pixel was an 800-nanometer-long square containing four aluminum nanodisks.

The plasmon resonance wavelength varies sensitively with the dimensions of the nanostructures. Consequently, by varying the diameter of the four aluminum nanodisks in a pixel (all four nanodisks having the same diameter), the scientists were able to produce about 15 distinct colors — a good start, but hardly enough to faithfully reproduce full-color images.

By allowing two pairs of diametrically opposite nanodisks to have different diameters from each other, then varying the two diameters enabled them to increase this number to over 100. Finally, they generated over 300 colors by varying both the nanodisk diameter (but keeping all four diameters within a pixel the same) and the spacing between adjacent nanodisks in a pixel (see image). “This method is analogous to half-toning used in ink-based printing and results in a broad color gamut,” comments Yang.

The researchers demonstrated the effectiveness of their extended palette using a Monet painting. They reproduced the image using both a limited and extended palette, with a much better color reproduction from the extended palette. Amazingly, they shrank the image from 80 centimeters to a mere 300 micrometers — a 2,600-fold reduction in size.

“The use of a more cost-effective metal has the potential to move this technology closer to adoption,” Tan notes.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering. More information about the group’s research can be found at the Plasmonic and Semiconductor Nanostructures Laboratory webpage.

Reference
Tan, S. J., Zhang, L., Zhu, D., Goh, X. M., Wang, Y. M. et al. Plasmonic color palettes for photorealistic printing with aluminum nanostructures. Nano Letters 14, 4023–4029 (2014). | article

A*STAR Research | ResearchSEA
Further information:
http://www.research.a-star.edu.sg/research/7166
http://www.researchsea.com

More articles from Materials Sciences:

nachricht Decoding cement's shape promises greener concrete
08.12.2016 | Rice University

nachricht Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D
08.12.2016 | DOE/Brookhaven National Laboratory

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>