Refraction of electromagnetic waves in pseudo-passive media

The problem of reflection and refraction of a plane monochromatic wave is considered in the most general formulation for a flat interface of two isotropic pseudo-passive media using the vector covariant approach of F.I. Fedorov. The generalized Fresnel coefficients for the perpendicular and parallel polarizations turn out to be complex values, except for cases when the phase difference of the permeabilities of the two media is zero or 180 degrees. The critical Brewster angles also turn out to be complex quantities. The phenomenon of total reflection, in contrast to passive transparent media, is not realized in pseudo-passive media. The energy coefficients of reflection and transmission are calculated and analyzed. Restrictions imposed on the values of the material parameters of the problem are indicated, which should be taken into account when studying refractive wave phenomena involving pseudo-passive metamaterials.

Intelligent reflected surfaces assisted code domain non-orthogonal multiple access scheme

The propagation medium plays a crucial role in any wireless communication networks, the channel between the transmitter and the receiver, deteriorate the quality of the received signal due to the uncontrollable interactions such as scattering, reflection, and refraction in the channel with the surrounding objects. To overcome this challenge, the recent advent of recongurable intelligent surfaces can be helpful, in which the network operators can control the radio waves, eg, the phase, amplitude, frequency, and even polarization, of the impinging signals without the need of complex decoding, encoding, and radio frequency processing operations. On the other hand, few research papers reported an efficient code domain non orthogonal multiple access (NOMA) such as Interleave division multiple access (IDMA) system for wireless information transfer. Persuaded by the capability of this arising RIS technology, the present article is aimed to provide the modified framework of IDMA (code-domain NOMA) communication system based on RIS technology. Simulation results demonstrate that the proposed system achieves better SNR performance than the conventional IDMA framework.

Transverse shifts and time delays of spatiotemporal vortex pulses reflected and refracted at a planar interface

Transverse (Hall-effect) and Goos–Hänchen shifts of light beams reflected/refracted at planar interfaces are important wave phenomena, which can be significantly modified and enhanced by the presence of intrinsic orbital angular momentum (OAM) in the beam. Recently, optical spatiotemporal vortex pulses (STVPs) carrying a purely transverse intrinsic OAM were predicted theoretically and generated experimentally. Here we consider the reflection and refraction of such pulses at a planar isotropic interface. We find theoretically and confirm numerically novel types of OAM-dependent transverse and longitudinal pulse shifts. Remarkably, the longitudinal shifts can be regarded as time delays, which appear, in contrast to the well-known Wigner time delay, without temporal dispersion of the reflection/refraction coefficients. Such time delays allow one to realize OAM-controlled slow (subluminal) and fast (superluminal) pulse propagation without medium dispersion. These results can have important implications in various problems involving scattering of localized vortex states carrying transverse OAM.

Devotional Reflections by Marvellous Mirrors

Jan David’s Duodecim specula (Antwerp: Officina Plantiniana, 1610) is a meditative emblem book, centred around myriad mirror metaphors. However, it also contains various depictions of ‘real’ optical instruments, such as lenses and concave mirrors, which have not yet been studied as such. This article explores how catoptrics and dioptrics (optical reflection and refraction) inform the meditative programme laid out in Duodecim specula. In the emblems and text, it will be argued, Jan David relies on a type of public knowledge of optics, which he expected the reader to possess. By tapping into this reservoir of optical knowledge and adding onto it, the book stimulates the affective reading process and hands the reader concrete tools for performing the meditative programme.