Related papers: Evolution and the Calcite Eye Lens
The chiton Acanthopleura granulata uses aragonitic lenses embedded in its shell to focus light onto photoreceptors. Because aragonite is biaxially birefringent, the microstructure of the lens greatly impacts the optical performance. In…
We study the optic control for birefringence of a polarized light by an atomic ensemble with a tripod configuration, which is mediated by the electromagnetically induced transparency with a spatially inhomogeneous laser. The atom ensemble…
Cylinder-shaped perfect lens deduced from the coordinate transformation method is proposed. The previously reported perfect slab lens is noticed to be a limiting form of the cylindrical lens when the inner radius approaches infinity with…
Precision in optical micromanipulation is critical for non-invasive, non-contact control of objects with light and for using light to measure forces and torques. We demonstrate the control of birefringent objects over three translational…
The construction of the multi-focal Veselago lens predicted earlier is proposed on the basis of a uniaxial photonic crystal consisting of cylindrical air holes in silicon that make a triangular lattice in a plane perpendicular to the axis…
The effects of calcein, a marker commonly used to assess mineral growth in calcifying organism, on calcite and aragonite structure have been investigated. Calcein is entrapped within calcite and aragonite and modifies the shape and…
Invisibility cloaks, a subject that usually occurs in science fiction and myths, have attracted wide interest recently because of their possible realization. The biggest challenge to true invisibility is known to be the cloaking of a…
Magnetic fields play a critical role in the propagation of charged cosmic rays. Particular field configurations supported by different astrophysical objects may be observable in cosmic ray maps. We consider a simple configuration, a…
Crystalline calcium-aluminates include the phases essential in the setting of Portland cements developed over the last century. It is only within recent decades, however, that calcium-aluminate melts and glasses have begun to attract…
Although the polymorphism of calcium carbonate is well known, and its polymorphs-calcite, aragonite, and vaterite-have been highly studied in the context of biomineralization, polyamorphism is a much more recently discovered phenomenon, and…
Birefringence ($\Delta n$) is the dependence of the refractive index of a material on the polarization of light travelling through it. Birefringent materials are used as polarizers, waveplates, and for novel light-matter coupling. While…
Many promising approaches for designing interactions of synthetic materials with light involve solid optical monocrystals and nanofabricated photonic crystal structures with spatially periodic variations of refractive index. Although their…
Arclets in clusters of galaxies can be used to determine the lens mapping and not only to constrain the mass density of the cluster. Multiply imaged arclets are therefore easily identified without further modelling.
Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most…
Galactic bulges are central to understanding galaxy formation and evolution. Here we report on recent studies using micro-lensing events to obtain spectra of high resolution and moderately high signal-to-noise ratios of dwarf stars in the…
Crystals are the elementary constituents of Laue lenses, an emerging technology which could allow the realization of a space borne telescope 10 to 100 times more sensitive than existing ones in the 100 keV - 1.5 MeV energy range. This study…
Clusters of galaxies acting as gravitational lenses deform the images of background galaxies. For small galaxies the deformation is determined by the local properties of the lens (shear, convergence). Small circular shaped galaxies are seen…
We describe a series of new applications of gravitational lenses as astrophysical and cosmological tools. Such applications are becoming possible thanks to advances in the quality and quantity of observations. CASTLES…
We report the discovery of transients among star clusters in a distant galaxy that is gravitationally lensed by a foreground galaxy cluster, and explore whether these transients correspond to: (i) intrinsic variations associated with…
Recently, there has been an explosion of interest in metalenses for imaging. The interest is primarily based on their sub-wavelength thicknesses. Diffractive lenses have been used as thin lenses since the late 19th century. Here, we show…