The goal of nanotechnology is often just duplicating what nature does. Whether it’s replicating the way that geckos walk on ceilings without falling down, or duplicating plants' use of photosynthesis to design improved solar cells, nature is the source of much inspiration and guidance in nanotech research.
Researchers at GE Global Research have found such inspiration from nature in their recent work in developing better thermal imaging.
The research, published in the journal Nature Photonics, was on “low-thermal-mass resonators inspired by the architectures of iridescent Morpho butterfly scales.”
The experiment involved the doping of Morpho butterfly scales with single-walled carbon nanotubes (SWNTs). When the researchers blew on butterfly wings coated with the SWNTs, the wings detected temperature changes down to a mere 0.02 degrees Celsius within 1/40 of a second.
"The iridescence of Morpho butterflies has inspired our team for yet another technological opportunity. This time we see the potential to develop the next generation of thermal imaging sensors that deliver higher sensitivity and faster response times in a more simplified, cost-effective design,” said Radislav Potyrailo, principal scientist at GE Global Research who leads GE’s bio-inspired photonics programs. “This new class of thermal imaging sensors promises significant improvement over existing detectors in their image quality, speed, sensitivity, size, power requirements, and cost.”
It should be noted that the SWNTs only enhance the heat absorption of the butterfly wings. The phenomenon occurs mainly because the wings are composed of nanoscale structures made of chitin. These structures create the reflections and refractions of light that our eyes perceive as the iridescence associated with this species of butterfly. The light effect is also caused by the expansion of the chitin when it absorbs infrared radiation.
The GE researchers were especially interested in chitin’s ability to expand by actually absorbing the infrared light, and it was this feature that they magnified by doping the wings with SWNTs.
While this is a very promising demonstration, it will likely take some time to convert these observations into any kind of device that could replace today's infrared detectors. However, the researchers are hopeful that the work they are doing with the Morpho butterfly in vapor sensing applications could reach the market as soon as five years.
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.