Brilliant whiteness in shrimp from ultra-thin layers of birefringent nanospheres

Abstract

A fundamental question regarding light scattering is how whiteness, generated from multiple scattering, can be obtained from thin layers of materials. This challenge arises from the phenomenon of optical crowding, whereby, for scatterers packed with filling fractions higher than ~30%, reflectance is drastically reduced due to near-field coupling between the scatterers. Here we show that the extreme birefringence of isoxanthopterin nanospheres overcomes optical crowding effects, enabling multiple scattering and brilliant whiteness from ultra-thin chromatophore cells in shrimp. Strikingly, numerical simulations reveal that birefringence, originating from the spherulitic arrangement of isoxanthopterin molecules, enables intense broadband scattering almost up to the maximal packing for random spheres. This reduces the thickness of material required to produce brilliant whiteness, resulting in a photonic system that is more efficient than other biogenic or biomimetic white materials which operate in the lower refractive index medium of air. These results highlight the importance of birefringence as a structural variable to enhance the performance of such materials and could contribute to the design of biologically inspired replacements for artificial scatterers like titanium dioxide.

Combined simulation and experimental study on spectral absorbance of partially disordered MoSe2 nanospheres

“…The optical simulation and numerical computation of the electromagnetic field propagation after the beam passing through the multilayer MoSe 2 nanospheres are calculated with the 3D FDTD method with the software of Lumerical FDTD solutions [17]. Multilayer MoSe 2 nanospheres represent the stacking dispersion of multiple elementary layers.…”

Undesired films with brilliant whiteness produced from a transparent amorphous polymer solution during room temperature evaporation or water washing

“…In fact, biomimetic ultrathin films with brilliant whiteness have been a research hotspot recently. 5,6 Considering human health and environmental friendliness, researchers prefer to prepare artificial white materials with specific structures inspired by living organisms such as Cyphochilus white beetle, 7,8 Morpho theseus juturna, 9 Lysmata amboinensis, 10 and Diphylleia grayi, 11 rather than relying on the use of high reflective index inorganic F I G U R E 1 Schematic image of (A) amorphous polymer film formation by the casting method and its undesired products: white PEI films from PEI solution (B) after room temperature evaporation at bottle mouth and (C) after water washing along with their respective equivalent experiments. materials such as TiO 2 (n = 2.6), ZnS (n = 2.4), or ZnO (n = 2.0).…”

“…12 To generate structural white, photons of all wavelengths must be scattered multiple times to produce broadband angle independent reflectance, which can be achieved by optimizing the combination of the single particle scattering (the form factor: particle refractive index, shape, and size) and the particle ensemble scattering (the structure factor: packing density and layer thickness). 10 Based on experimental analysis and computer simulation results of the above organisms, a series of methods for preparing biomimetic structures with bright structural white have been proposed. Syurik fabricated 9 μm thin porous PMMA films with a reflectance above 57% by foaming with CO 2 saturation.…”

Surface‐Guided Crystallization of Xanthine Derivatives for Optical Metamaterial Applications

“…[18][19][20] Most of the effort has been invested in the research of semiconducting crystals built from aromatic conjugated macrocyclic molecules, [21][22][23][24] with little attention to dielectric crystals constructed from small aromatic molecules. [25,26] This is despite the broad use of thin-film multilayer dielectric structures in optics and some clear advantages that seem to emerge from the use of highly birefringent organic crystals for optical applications, including a controlled polarization response [27] and enhanced scattering, [28] as has been shown for biogenic systems.…”