Subscribe free to our newsletters via your
  Nano Technology News  

Subscribe free to our newsletters via your

Shiny fish skin inspires nanoscale light reflectors
by Staff Writers
University Park PA (SPX) Jan 18, 2016

A transmission electron microscope image of ribbonfish skin shows random arrangements of crystalline quinine embedded in cytoplasm (a). The arrangement of crystal layers reflects light across a broad spectrum. The cytoplasm and crystal layers are reproduced in (b) - red dotted line (5 mm scale bar) and then turned into a fractal pattern with random changes introduced in (c). Image courtesy Werner Group and Penn State. For a larger version of this image please go here.

A nature-inspired method to model the reflection of light from the skin of silvery fish and other organisms may be possible, according to Penn State researchers.

Such a technique may be applicable to developing better broadband reflectors and custom multi-spectral filters for a wide variety of applications, including advanced optical coatings for glass, laser protection, infrared imaging systems, optical communication systems and photovoltaics, according to Douglas Werner, John L. and Genevieve H. McCain Chair Professor in Electrical Engineering, Penn State.

The proposed model also contributes to the understanding of the reflective layering in the skin of some organisms. The shiny skins of certain ribbonfish reflect light across a broad range of wavelengths, giving them a brilliant metallic appearance.

The reflectivity is the result of stacked layers of crystalline organic compounds embedded in their skin's cytoplasm. Some organisms with metallic sheens have layers that are stacked in a regular pattern, while others, including the ribbonfish, have stacking patterns described as "chaotic" or random. The Penn State team determined that the stacking is not completely random and developed mathematical algorithms to replicate those patterns in semiconductor materials.

"We are proposing a model that uses fractal geometry to describe the layering in the biological structure of silvery fish," says Jeremy Bossard, postdoctoral researcher in electrical engineering, Penn State. "While we are not trying to reproduce the structure found in nature, the same model could guide the design of devices such as broadband mirrors."

Fractals have been called the "geometry of nature" because they can help describe the irregular but self-similar patterns that occur in natural objects such as branching tree limbs. The researchers use a one-dimensional fractal, known as a Cantor bar fractal, which is a line divided by spaces or gaps.

Normally, Cantor fractals appear to be very regular, but when random changes are introduced to the geometry, a more complex pattern emerges. The pattern resembles the layering of reflective layers in ribbonfish skin.

"There is an underlying pattern, but there is randomness built in," says Bossard, "similar to the way that living trees have an overall fractal pattern but do not grow symmetrically."

The researchers then use another nature-inspired computational method called a genetic algorithm that mimics Darwinian evolution to create successive generations of fractal patterns from the parent patterns. Over approximately 100 generations, the patterns converge on the best design to meet all the target requirements.

Using these fractal random Cantor bars and the genetic algorithm, the researchers were able to mathematically generate patterns targeting optical functions in the mid-infrared and near-infrared ranges, including broadband reflection. They propose that the design approach could be used to develop nanoscale stacks with customized reflective spectra.

The research results are reported in the January 13, 2016 issue of the Journal of the Royal Society Interface in "Evolving random fractal Cantor superlattices for the infrared using a genetic algorithm." Lan Lin, a recent Ph.D. graduate in electrical engineering, also contributed to the work and performed materials fabrication and characterization for the project.


Related Links
Penn State
Nano Technology News From
Computer Chip Architecture, Technology and Manufacture

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Previous Report
Electronically connected graphene nanoribbons foresee high-speed electronics
Sendai, Japan (SPX) Jan 15, 2016
An international research team at Tohoku University's Advanced Institute of Materials Research (AIMR) succeeded in chemically interconnecting chiral-edge graphene nanoribbons (GNRs) with zigzag-edge features by molecular assembly, and demonstrated electronic connection between GNRs. The GNRs were interconnected exclusively end to end, forming elbow structures, identified as interconnection point ... read more

Airbus forms joint venture in bid for Canadian contract

Belgian aerospace company expands into Romania

Researchers Advance Propulsion Toward Low-Carbon Aircraft

Thousands protest over contested French airport site

China plans 20 launches in 2016

China's Belt and Road Initiative catches world's imagination: Inmarsat CEO

China launches HD earth observation satellite

Chinese rover analyzes moon rocks: First new 'ground truth' in 40 years

McAfee shifts presidential run, unveils cybersecurity plan

CACI wins place on DIA tech support contract

China says Communist Party to be 'strongest voice in cyberspace'

Microsoft to warn users about 'nation-state' intrusion

What motivates people to walk and bike? It varies by income

Energy efficiency may encourage greater demand

Global electricity production vulnerable to climate and water resource change

Improving electric motor efficiency via shape optimization

Unique 2-level cathode structure improves battery performance

A different way to make cathodes may mean better batteries

Companies mostly dump their coal ash in poor, minority communities

Creation of Jupiter interior, a step towards room temp superconductivity

Indian Army likely to get K9 Vajra-T howitzers

Saab to provide more equipment for U.S. Army combat vehicles

Hundreds of vehicles ordered for French Special Forces

US general fears military will lower standards for women

Annihilating nanoscale defects

Mechanical properties of nanomaterials are altered due to electric field

Electronically connected graphene nanoribbons foresee high-speed electronics

New approach for controlled fabrication of carbon nanostructures

Microbots individually controlled using 'mini force fields'

New social robot Nadine has a personality

Human-machine superintelligence can solve the world's most dire problems

NTU scientists unveil social and telepresence robots

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.