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Previous studies on spacetime index of refraction are mostly restricted to the static spacetimes. In this study we fill this gap by introducing the refractive index for full stationary spacetimes, employing three different approaches. These…

General Relativity and Quantum Cosmology · Physics 2025-07-10 F. Masghatian , M. Esfandiar , M. Nouri-Zonoz

The physical origins of negative refractive index are derived from a dilute microscopic model, producing a result that is generalized to the dense condensed phase limit. In particular, scattering from a thin sheet of electric and magnetic…

Optics · Physics 2009-11-10 David W. Ward , Keith A. Nelson , Kevin J. Webb

Studied experimentally the origin of the non-zero reflection of p-polarized radiation (TM) of Brewster's angle. The results have shown the residual reflected light in the vicinity of Brewster angle occurs due to inaccessibility 100%…

Optics · Physics 2015-10-26 Eugene A. Tikhonov

With the development of terahertz time-domain spectroscopy, methods have been proposed to precisely estimate the thickness, refractive index, and attenuation coefficient of a sample. In this article, we propose a new method to compute these…

Exact analytical results (in terms of Bessel functions) for the bandgaps, reflectance, and transmittance of one-dimensional photonic crystals with a sawtooth refractive index profile on the period are derived for the first time. This…

Optics · Physics 2013-03-12 G. V. Morozov , D. W. L. Sprung , J. Martorell

Negative refraction is known to occur in materials that simultaneously possess a negative electric permittivity and magnetic permeability; hence they are termed negative index materials. However, there are no known natural materials that…

Achromatic combinations of a diffractive Phase Fresnel Lens and a refractive correcting element have been proposed for X-ray and gamma-ray astronomy and for microlithography, but considerations of absorption often dictate that the…

Astrophysics · Physics 2009-11-10 Gerald K. Skinner

The formula for the lens is derived based on the information of instantaneous focal function. Focal function is an important tool in designing lenses with extended depth of focus (EDoF) because this allows EDoF lens designers to try out…

Optics · Physics 2009-02-04 Sung Nae Cho

A lens limited by diffraction and having two parabolic surfaces is presented. The knowledge of the following parameters: object distance, relative refractive index, lens thickness, and image distance, enables to analytically calculate the…

Optics · Physics 2020-08-10 Juan Camilo Valencia-Estrada , Jorge García-Márquez

We develop an iterative approach to gravitational lensing theory based on approximate solutions of the null geodesic equations. The approach can be employed in any space-time which is ``close'' to a space-time in which the null geodesic…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Thomas P. Kling , Ezra T. Newman , Alejandro Perez

Iterative projection algorithms are successfully being used as a substitute of lenses to recombine, numerically rather than optically, light scattered by illuminated objects. Images obtained computationally allow aberration-free…

Optics · Physics 2007-05-23 S. Marchesini

Conformal transformation optics provides a simple scheme for manipulating light rays with inhomogeneous isotropic dielectrics. However, there is usually discontinuity for refractive index profile at branch cuts of different virtual Riemann…

Optics · Physics 2018-02-08 Lin Xu , Tomáš Tyc , Huanyang Chen

The article presents a straightforward experiment that directly and illustratively demonstrates double refraction. For this purpose, two liquid crystalline cells were designed, which enable qualitative and quantitative measurements of the…

Soft Condensed Matter · Physics 2013-01-24 Jerneja Pavlin , Natasa Vaupotic , Mojca Cepic

In this geometrical approach to gravitational lensing theory, we apply the Gauss-Bonnet theorem to the optical metric of a lens, modelled as a static, spherically symmetric, perfect non-relativistic fluid, in the weak deflection limit. We…

General Relativity and Quantum Cosmology · Physics 2008-12-18 G W Gibbons , M C Werner

This paper uses the Schwarzschild metric to derive an effective refractive index and acceleration vector that account for relativistic deflection of light rays, in an otherwise classical kinematic framework. The new refractive index and the…

Astrophysics of Galaxies · Physics 2015-05-19 S. J. Walters , L. K. Forbes , P. D. Jarvis

To study the scattering properties of metamaterials, we generalize two scattering methods developed for conventional (non-magnetic) isotropic materials to the case of materials with arbitrary values (positive or negative) of magnetic…

Optics · Physics 2011-02-15 Vivian Grunhut , Ricardo A. Depine

We consider the geometrical optics for refraction of a distant radio source by an interstellar plasma lens, with application to a lens with a Gaussian electron column density profile. The refractive properties of the lens are specified…

Astrophysics · Physics 2009-10-30 Andrew W. Clegg , Alan L. Fey , T. Joseph W. Lazio

Specially designed metal-dielectric composites can have a negative refractive index in the optical range. Specifically, it is shown that arrays of single and paired nanorods can provide such negative refraction. For pairs of metal rods, a…

We explore the effects of incorporating negative index materials into the physics of time-varying media and find that changing the refractive index from positive to negative creates a perfect time-reversed wave: a perfect time-domain lens.…

Optics · Physics 2025-12-04 Oded Schiller , Yonatan Plotnik , Guy Bartal , Mordechai Segev

We carefully examine the negative refractive index slab perfect lens theory by Pendry and point out an inconsistency that can be resolved. As a result, we find negative index slabs do not amplify or enhance evanescent waves and therefore…

Optics · Physics 2008-07-14 Weiguo Yang , John O. Schenk , Michael A. Fiddy