Space-variant polarization patterns present in the transverse mode of optical beams highlight disclination patterns of polarization about a singularity, often a C-point. These patterns are important for understanding rotational dislocations and for characterizing complex polarization patterns. Liquid-crystal devices known as q-plates have been used to produce two of the three types of disclination patterns in optical beams: lemons and stars. Here we report the production of the third type of disclination, which is asymmetric, known as the monstar. We do so with elliptically-symmetric q-plates. We present theory and measurements, and find excellent agreement between the two.

Nacre is a complex biomaterial made of aragonite-tablet bricks and organic mortar that is considerably resilient against breakage. Nacre has been studied with a wide range of laboratory techniques, leading to understanding key fundamentals and informing the creation of bio-inspired materials. In this article, we present an optical polarimetric technique to investigate nacre, taking advantage of the translucence and birefringence of its microcomponents. We focus our study on 3 classes of mollusks that have nacreous shells: bivalve (Pinctada fucata), gastropod (Haliotis asinina and Haliotis rufescens) and cephalopod (Nautilus pompilius). We sent polarized light from a laser through thin samples of nacre and did imaging polarimetry of the transmitted light. We observed clear distinctions between the structures of bivalve and gastropod, due to the spatial variation of their birefringence. The patterns for cephalopod were more similar to bivalve than gastropod. Bleaching of the samples disrupted the transmitted light. Subsequent refilling of the bivalve and gastropod nacre samples with oil produced optical patterns similar to those of unbleached samples. In cephalopod samples, we found that bleaching produced irreversible changes in the optical pattern.

Nacre, or mother of pearl, is a complex self‐assembled biomaterial that has high resistance against breakage. It is made of micronsized aragonite‐crystal tablets embedded in organic matter, in a brick‐and‐mortar type of structure. Analysis of the transformation of polarized light passing through this natural structure reveals the great uniformity of the layered arrangement of bivalve nacre (left image), and quite distinctly, the non‐uniform columnar structure of gastropod nacre (right image). Further details can be found in the article by Joshua A. Jones, Rebecca A. Metzler, Anthony J. D'Addario et, al. (https://doi.org/10.1002/e201800026).

A system is developed for simulating the image quality and dysphotopsia of multifocal lenses. To achieve this, the simulation modifies a High Dynamic Range (HDR) photograph by blurring it with the lens' point spread function in MATLAB. Dysphotopsias are instances of unwanted or missing light within the eye. Common forms of dysphotopsia include glare, starburst (radial lines emanating from bright sources), and halo (rings of light surrounding bright sources) with the latter two typically occurring at night or in other high contrast settings. Dysphotopsia is considered the most common complaint of patients after successful cataract surgery and have thus earned significant attention in the context of intraocular lenses (IOLs). There have been fewer studies of multifocal contact lens dysphotopsia, but this is despite the documented impact dysphotopsia has on the image quality of multifocal lenses. This simulation is the first handling of dysphotopsia that combines HDR images and specifics of the lens design to predict how the dysphotopsia will appear to patients. Being able to show patients accurate simulations of dysphotopsia has the benefit of setting proper patient expectations before they begin using multifocal lenses. Furthermore, these simulated images can also potentially help diagnose patient problems by giving patients an accurate baseline to compare to.

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