University of Surrey Replicates Butterfly Wing Structures Using 3D Printed Ceramics

Just about everyone loves butterflies, I think, even people who hate insects in general. It’s hard not to be amazed by their beauty and the incredible variety of colors they display; I’ve heard them compared to living, flying jewels multiple times, and it’s an accurate description. How many people, however, while marveling at a brilliantly colored butterfly, pause to think about exactly how that color is manifested? Other than scientists, probably not many – but even the most knowledgeable scientists still have questions about how nature creates those jewel tones.

Researchers from the University of Surrey recently made a discovery not just about how such colors are produced, but how humans can replicate them. A team led by senior lecturer Dr. Marian Florescu conducted a study into the photonic band gap in structured photonic materials – in other words, they researched what makes certain materials block certain wavelengths. During the study, they discovered that the internal structures of natural materials have a direct impact on their ability to diffuse absorb, reflect and transmit light.

Specifically, the team found a relationship between the uniformity of the internal structure of natural materials at wavelength scale and the ability of said material to block certain wavelengths. They then developed a mathematical method to determine which types of photonic structures most effectively control the propagation of light. That’s where the butterflies come in. As the researchers tested their theory, they developed an unprecedented amorphous gyroid, or triamond, structure with band gaps – very similar to the structure of certain butterfly wings, in particular the wings of the Pseudolycaena marsyas, also known as the Cambridge blue or giant hairstreak butterfly. Using a 3D ceramic printer, they were able to reproduce the structure, creating the first-ever 3D printed alumina photonic band gap material.

While other researchers have also used 3D printing to recreate color as nature makes it, the University of Surrey study has implications far beyond just replicating the hues of butterflies. The structures the researchers created in the lab, like their natural counterparts, can absorb and reflect not only light but sound and heat waves, meaning that they could be used to create materials like heat-rejecting window films and paints, which could improve the energy efficiency of buildings and vehicles.

“It is truly amazing that what we thought was an artificial design could naturally be present in nature,” said Dr. Florescu. “This discovery will impact how we design materials in the future to manipulate their interaction with light, heat and sound.”

The research answered a question that scientists in the field of photonic crystal research have been trying to answer for 25 years: where does the photonic gap in three-dimensional diamond-like and two-dimensional honeycomb dielectric networks come from?

Clockwise from top left: Dr. Marian Florescu, Sherwin Sahba, Weining Man and Steven Sellers.

“Our formalism is finally able to answer this fundamental question with simple geometrical/topological metric without the need of electromagnetic simulations: the champion PBG structures correspond to network that maximize the local self-uniformity, namely strongly isotropic networks,” continued Dr. Florescu. “The advantages of triamond-amorphous-enabled photonic devices include improved fabrication tolerance, layout flexibility, and isotropy, will provide a compelling case in the optical component and sub-system markets, and novel solutions for more energy- efficient materials.”

The research was published in an article entitled “Local uniformity in photonic networks,” which can be accessed here. Additional authors include Steven Sellers, Weining Man and Shervin Sahba. The University of Surrey has filed a British patent application for the technology, and an international patent is also being pursued. In addition, the university is looking into commercializing a new, more compact and energy-efficient structured material in partnership with Etaphase Inc. Discuss in the University of Surrey forum at 3DPB.com.

[Source: Optics.org]