Fireflies are a lifelong favorite insect and I celebrate their arrival every summer. Their fascinating pyrotechnics produced as they search for mates are a constant source of amazement providing entertainment for hours during those enchanted summer evenings.
Now their highly efficient bioluminescent structure is a source of inspiration and study for Korean researchers who are attempting to create an anti-reflective lens for light-emitting diodes (LED) based on morphological structures of the firefly lantern.
A team of researchers at the Korea Advanced Institute of Science and Technology have examined the intricate nanostructure of the firefly’s lantern cuticle and created an artificial version for use as a high-power LED lens.
In a paper published in the Proceedings of the National Academy of Sciences, the scientists describe how they produced a new LED lens by copying the structure of the firefly’s three-layered lower abdomen. This newly refined lens allows them to do away with an expensive component in existing LED lamps.
It was known that the firefly’s lantern is made up of a luminous layer, a nanostructured cuticle layer and a dorsal layer that allow for highly efficient generation of bioluminescent light. Exactly how the dorsal and cuticle layers work together in this photonic system was not understood.
Using a scanning electron microscope Jae-Jun Kim and colleagues at Ki-Hun Jeong’s lab at the Institute determined the intricate nanostructure of the lantern’s cuticle Their experiments revealed that the highly ordered structure reduces optical impedance between air and the cuticle, effectively acting as an anti-reflective layer to reduce loss of light and increase efficiency.
Engineering inspiration from highly ordered cuticular nanostructures of a firefly light organ. (A) The optical image of a firefly (L. lateralis Motschulsky) in male. The SEM images of (B) abdominal segments of a firefly in male including normal (N) and lantern (L) cuticles, (C) amorphous nanostructures on the normal cuticle, (D) highly ordered nanostructures on the lantern cuticle.
A high power LED dome lens is impeded by the internal reflection of light due to optical disparity between air and the lens material. Once the cuticular nanostructures of the firefly lantern were determined the team was able to incorporate this composition on the lens of a high power LED to increase the light extraction efficiency. The team considers their work a first in using “engineering biomimetics”- mimicking a bioluminescent organ in an artificial lighting application.
Firefly pictures from: http://www.firefly.org/
To read more about this research go to Proceedings of the National Academy of Sciences