We review the intensively discussed ideas about wave propagation and refraction in media where both electric permittivity and magnetic permeability are negative. The criticism against negative refraction as violating the causality principle is considered. Starting from the initial wave equations, refraction of beams at the boundary of a lefthanded medium is analyzed. The physics of a perfect le...

We have found three lenses (two are new) by observing 34 likely FIRST radio lobes with APM galaxy counterparts. We expect to find ∼ 30 such lenses in over the next few years, which will significantly improve lensing constraints on galaxy structure and cosmology. Although ∼70% of lensed radio sources should be radio lobes (Kochanek & Lawrence 1990) few have been found. In fact, many radio search...

The perturbative approach for describing the underdense plasma–ultrarelativistic electron bunch system is developed,using the ratio n0 nb as a small parameter (nb-bunch,n0plasma electron densities). Focusing of the electron bunch emerged in the first approximation of the perturbative procedure as a result of the plasma electrons redistribution.Focusing gradient and strength for ultrarelativisti...

PURPOSE The purpose of this study is to develop and analyze a method to obtain optical schematic models of individual eyes. Each model should be able to reproduce the measured monochromatic wave aberration with high fidelity. METHODS First, we choose a generic eye model as the input guess and then apply a two-stage customization procedure. Stage 1 consists of replacing, in the initial generic...

We review the intensively discussed ideas about wave propagation and refraction in media where both electric permittivity and magnetic permeability are negative. The criticism against negative refraction as violating the causality principle is considered. Starting from the initial wave equations, refraction of beams at the boundary of a left-handed medium is analyzed. The physics of a perfect l...

Abstract. Natural wormholes and its astrophysical signatures have been sugested in various oportunities. By applying the strong field limit of gravitational lensing theory, we calculate the deflection angle produced by Morris-Thorne wormholes in asimptotically flat space-times. The results show that wormholes act like convergent lenses. Therefore it is hard to distinguish them from black holes ...