Improved light extraction in the bioluminescent lantern of a Photuris firefly (Lampyridae)

Abstract

A common problem of light sources emitting from an homogeneous high-refractive index medium into air is the loss of photons by total internal reflection. Bioluminescent organisms, as well as artificial devices, have to face this problem. It is expected that life, with its mechanisms for evolution, would have selected appropriate optical structures to get around this problem, at least partially. The morphology of the lantern of a specific firefly in the genus Photuris has been examined. The optical properties of the different parts of this lantern have been modelled, in order to determine their positive or adverse effect with regard to the global light extraction. We conclude that the most efficient pieces of the lantern structure are the misfit of the external scales (which produce abrupt roughness in air) and the lowering of the refractive index at the level of the cluster of photocytes, where the bioluminescent production takes place.

Optimal overlayer inspired by Photuris firefly improves light-extraction efficiency of existing light-emitting diodes

“…A former study on Photuris has revealed an interesting structure on the outer cuticle of the firefly [22,23]. Figure 1(b) shows a Scanning Electronic Microscope (SEM) image of the outer cuticle.…”

“…This pattern is directly inspired by the microstructure found in the firefly Photuris sp. (Lampyridae) [22,23], with the particularity to be created on an overlayer, added as a supplementary layer, on an existing LED structure.…”