The importance of Mie resonances in ultra-black dragonfish skin pigment particles

The ultra-black skin of the deep-sea dragonfish consists of small pigment particles which together provide optimal light absorption to prevent detection from bioluminescent predators or prey. The mechanism of light absorption in these pigment particles resembles the nanophotonic approaches to increase solar cell efficiency via Mie scatter-ing and resonances. In this work, the Mie resonance responses of dragonfish pigment particles were inves-tigated with finite-difference time-domain (FDTD) simulations to elucidate the exact mechanism respon-sible for the ultra-black skin of the dragonfish. Ellip-soidal pigment particles were found to have superior light absorption over spherical pigment particles. The pigment particles were also shown to exhibit forward scattering, demonstrating an important feature for repeated light absorption in pigment-containing skin layers. Although this work contributes to a deeper understanding of the ultra-back skin of the dragon-fish, the nanophotonic mechanisms proposed here are likely more general, and could be applied to photo-voltaic light management designs and immunometric detection based on light extinction