Empirical BRDF Model for Goniochromatic Materials and Soft Proofing With Reflective Inks.

The commonly used analytic bidirectional reflectance distribution functions (BRDFs) do not model goniochromatism, that is, angle-dependent material color. The material color is usually defined by a diffuse reflectance spectrum or RGB vector and a specular part based on a spectral complex index of refraction. Extension of the commonly used BRDFs based on wave theory can help model goniochromatism, but this comes at the cost of significant added model complexity.

Iridescence Mimicking in Fabrics: A Ultraviolet/Visible Spectroscopy Study.

Poly(styrene-methyl methacrylate-acrylic acid) photonic crystals (PCs), with five different sizes (170, 190, 210, 230 and 250 nm), were applied onto three plain fabrics, namely polyamide, polyester and cotton. The PC-coated fabrics were analyzed using scanning electronic microscopy and two UV/Vis reflectance spectrophotometric techniques (integrating sphere and scatterometry) to evaluate the PCs' self-assembly along with the obtained spectral and colors characteristics. Results showed that surface roughness of the fabrics had a major influence on the color produced by PCs.

Full-color holographic display with increased-viewing-angle [Invited].

Among the important features of holographic displays are the wide viewing angles and the full color of the reconstructed images. The present work focuses on achievement of both features. We propose an increased-viewing-angle full-color holographic display using two tiled phase-only spatial light modulators (SLMs), a 4f concave mirrors system, and a temporal-spatial multiplexing method.

Modeling of light interaction with exoskeletons of scarab beetles.

Some beetles of the family Scarabaeidae produce brilliant metallic-looking colors by their pure dielectric exoskeletons and reflect light with a high degree of circular polarization. In the present work, we discuss three models for simultaneously describing scattering, spectral, and polarization characteristics of scarab beetles. Each model consists of three slabs: an outer thin epicuticle, an exocuticle having a helicoidal structure, and a thick uniform slightly absorbing endocuticle.

Simulation of light scattering from exoskeletons of scarab beetles.

An approach for simulation of light scattering from beetles exhibiting structural colors originating from periodic helicoidal structures is presented. Slight irregularities of the periodic structure in the exoskeleton of the beetles are considered as a major cause of light scattering. Two sources of scattering are taken into account: surface roughness and volume non-uniformity.

Assessment of minimum permissible geometrical parameters of a near-to-eye display.

Light weight and small dimensions are some of the most important characteristics of near-to-eye displays (NEDs). These displays consist of two basic parts: a microdisplay for generating an image and supplementary optics in order to see the image. Nowadays, the pixel size of microdisplays may be less than 4 μm, which makes the supplementary optics the major factor in defining restrictions on a NED dimensions or at least on the distance between the microdisplay and the eye.

Curved-lattice epitaxial growth of In(x)Al(1-x)N nanospirals with tailored chirality.

Chirality, tailored by external morphology and internal composition, has been realized by controlled curved-lattice epitaxial growth of In(x)Al(1-x)N nanospirals. The curved morphology of the spiral segments is a result of a lateral compositional gradient while maintaining a preferred crystallographic growth direction, implying a lateral gradient in optical properties. Individual nanospirals show an asymmetric core-shell structure with curved basal planes.