Computer Chips Borrow From Butterflies

Tracy Staedter


Some butterfly wings get some of their iridescent color from light reflecting off tiny structures in the scales of their wings.
Now scientists have devised a simple process to replicate those structures, called photonic crystals. Such crystals could significantly improve communication systems or computer chips by transmitting information — not with electrons, as is currently done — but with particles of light.

"Photonic crystals promise to give us control over photons with even greater flexibility because we have far more control over the properties of photonic crystals than we do over the electronic properties of semiconductors," explained Wang Zhang, a Ph.D. candidate at the State Key Lab of Metal Matrix Composites, Shanghai Jiaotong University in Shanghai, China.
Some photonics devices, such as fiber optic cables and lasers, are commonplace technologies. But researchers would like to perfect the art of manipulating photons from a wide range of the light spectrum to develop efficient devices.
For instance, a DVD that works using an ultraviolet light source, instead of a laser, could store more than 200 gigabytes of information.

Computer chips could also employ photons, instead of electrons, to process signals. With this capability, data inside a computer would get shuttled between components as light and move 10 times faster than if it were electricity.

But finding a way to harness the various wavelengths of light has been a challenge and current methods are expensive and labor-intensive.
Wang and his team believe that nature holds the answer.
To replicate the physical and optical properties of butterfly wings, Zhang and his team of researchers coated wing scales with zinc oxide (a substance that is also used as a pigment in paint).
Once coated, the scales were heated to 800 degrees Celsius. The heat crystallized the zinc and burned off the original butterfly wing scale.
The result was a crystal-like, three-dimensional material that retained the light-splitting structures of the butterfly wing.
The researchers think that replicas could be used in experiments to test different theories about the properties of photons. They also hope the bio-mimetic structures could be used as molds to efficiently fabricate replicas for use in photonic devices.

"I think it's fairly original. They are trying to transfer these complex three-dimensional butterfly scales to commerce," said Andrew Parker, a research fellow at Green College in Oxford, England and a research leader in the department of zoology at the Natural History Museum in London.
But competition in this field is stiff. Parker says physics labs in just about every university are trying to create photonic crystals and it's going to be decades before a winner emerges.

"At some stage somebody is going to find an application for these structures in computer chips and communication systems, but we'll need to wait another 20 years to see who," he said.