1,721,048 research outputs found
Gaussian model for refractive indexes of columnar thin films and Bragg multilayers [Opt. Commun. 231 (1-6) (2004) 257-261] DOI:10.1016/j.optcom.2003.12.030
No full textDesign of wideband circular-polarization filters made of chiral sculptured thin films
No full textCascades of chiral sculptured thin films (STFs) with successive pitches forming a geometric series are theoretically shown to junction as wideband circular-polarization filters. A simple design paradigm is provided
Gaussian model for refractive indexes of columnar thin films and Bragg multilayers
No full textWe characterize both the ordinary and extraordinary refractive indexes of columnar thin films (CTFs) as Gaussian functions of the vapor incidence angle. This simple model is compared to the one available in literature for three different materials, resulting in low relative errors. The Gaussian model can be easily used to design Bragg multilayers made of CTFs
Extension of Hodgkinson's model for optical characterization of columnar thin films
No full textAn extension of Hodgkinson's model for the principal refractive indexes and column-inclination angle of a columnar thin film against the vapor-incidence angle is presented for an extraordinary refractive index relevant,for many optical applications. Not only do the principal refractive indexes depend quadratically on the vapor incidence angle, but the extraordinary refractive index does as well. This model is expected to be valid for chiral sculptured thin films as well
Transformation optics, isotropic chiral media and non-Riemannian geometry
No full textCopyright © 2011 IOP Publishing Ltd and Deutsche Physikalische GesellschaftOpen Access journalArticle published under a Creative Commons Attribution 3.0 Unported (CC-BY) licenseThe geometrical interpretation of electromagnetism in transparent media (transformation optics) is extended to include chiral media that are isotropic but inhomogeneous. It was found that such media may be described through introducing the non-Riemannian geometrical property of torsion into the Maxwell equations, and it is shown how such an interpretation may be applied to the design of optical devices.
GENERAL SCIENTIFIC SUMMARY
Introduction and background. On a macroscopic scale, electromagnetism in a transparent material can be understood in terms of an average polarization and magnetization of the medium. This has been known for a long time, but it certainly isn't well adapted for the design of optical devices. Transformation optics is a recent development that makes use of the finding that Maxwell's equations in a curved space–time geometry take the same form as they do in a material. An effective permittivity and permeability can be derived from the measure of length and, in short, we can design optical devices with geometry. This approach has famously brought us designs for cloaking devices and 'sub-diffraction' lenses, as well as the investigation of analogues of astrophysical effects, such as Hawking radiation, in the laboratory.
Main results. In this paper it is found that the relationship between transparent materials and geometry goes further than was previously thought. Not only are curved space–times equivalent to materials, but some materials can be understood in terms of geometrical ideas that go beyond just curvature (i.e. beyond the mathematics of general relativity). In particular, it is found that light propagation in a geometry exhibiting space–time torsion (see figure) is equivalent to propagation through a chiral medium (space–time torsion can be related to optical activity). Such a finding can be applied to the design of optical devices. It allows us to incorporate chiral media into transformation optics, and has an immediate use—allowing for the independent control of polarization within transformation optics.
Wider implications. Incorporating chiral media into transformation optics may well reinvigorate the investigation of useful optical devices based on chiral media, which attracted attention in the past. There is also a fundamental interest in the close investigation of materials that mimic space–time torsion, as it is expected to play a prominent role in the physics of gravity beyond general relativity
Electromagnetic surface waves guided by the interface of a metal and a tightly interlaced matched ambidextrous bilayer
No full textNarrowband, linear-polarization rejection filter based on columnar thin film superlattice
No full textLeft/right asymmetry of the dipole field due to reflection from a periodic multilayer of a topological insulator and a columnar thin film
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Theory of thin film, narrowband, linear polarization rejection filters with superlattice structure - Optics Communications (2006) 268:1 (182-188)
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