arXiv subjects

Fei Li

Publications and source records attributed to Fei Li.

279 records · Page 16Linked to original sources

arXiv2006

Brewster's angle for anisotropic material from the extinction theorem

By the extinction theorem we explore the Brewster effect in the external and internal reflections of electromagnetic wave associated with an anisotropic material that is both dielectric and magnetic, including metamaterials. We obtain Fresnel's coefficients and the condition of Brewster's angle, and give microscopic explanations from the view point of molecular optics. The Brewster angle is the incidence of angle at which the contribution of all electric and magnetic dipoles in the anisotropic material to the reflection field becomes zero. Distinct from isotropic media, the anisotropic material can exhibit Brewster angle for both TE and TM waves due to the anisotropy of the material.

physics.optics↗

arXiv2006

Anomalous wave propagation in quasiisotropic media

Based on boundary conditions and dispersion relations, the anomalous propagation of waves incident from regular isotropic media into quasiisotropic media is investigated. It is found that the anomalous negative refraction, anomalous total reflection and oblique total transmission can occur in the interface associated with quasiisotropic media. The Brewster angles of E- and H-polarized waves in quasiisotropic media are also discussed. It is shown that the propagation properties of waves in quasiisotropic media are significantly different from those in isotropic and anisotropic media.

physics.optics↗

arXiv2006

Extinction theorem and propagation of electromagnetic waves between two semi-infinite anisotropic magnetoelectric materials

Based on molecular optics we investigate the reflection and refraction of an electromagnetic wave between two semi-infinite anisotropic magnetoelectric materials. In terms of Hertz vectors and the principle of superposition, we generalize the extinction theorem and derive the propagation characteristics of wave. Using these results we can easily explain the physical origin of Brewster effect. Our results extend the extinction theorem to the propagation of wave between two arbitrary anisotropic materials and the methods used can be applied to other problems of wave propagation in materials, such as scattering of light.

physics.optics↗

arXiv2006

Simultaneous slow phase and group velocities of light in an anisotropic metamaterial

We study theoretically the effect of ultraslow phase and group velocities in an anisotropic metamaterial. The ultraslow phase propagation is induced by the hyperbolic dispersion relation. While the inherent physics underlying the slow group velocity are collective operations of the frequency and spatial dispersion. We show that a Gaussian wave packet exhibits simultaneous slow phase and group velocities which depend on the choice of incident angles and principal axis angles. The anisotrocpic metamaterial slab can be constructed and the ultraslow phase and group velocities can be measured experimentally.

physics.optics↗

arXiv2006

Omnidirectional total transmission at the interface associated with an anisotropic dielectric-magnetic metamaterial

Based on the Ewald-Oseen extinction theorem, the omnidirectional total transmission of waves incident from vacuum into an anisotropic dielectric-magnetic metamaterials is investigated. It is shown that the omnidirectional total transmission need not limit at the interface associated with the conventional nonmagnetic anisotropic medium. The recent advent of a new class of anisotropic dielectric-magnetic matermaterial make the omnidirectional total transmission become available. It is found that the inherent physics underlying the omnidirectional total transmission are collective contributions of the electric and magnetic responses.

physics.optics↗

arXiv2006

Superluminal group velocity in an anisotropic metamaterial

Based on boundary condition and dispersion relation, the superluminal group velocity in an anisotropic metamaterial (AMM) is investigated. The superluminal propagation is induced by the hyperbolic dispersion relation associated with the AMM. It is shown that a modulated Gaussian beam exhibits a superluminal group velocity which depends on the choice of incident angles and optical axis angles. The superluminal propagation does not violate the theory of special relativity because the group velocity is the velocity of the peak of the localized wave packet which does not carry information. It is proposed that a triglycine sulfate (TGS) crystal can be designed and the superluminal group velocity can be measured experimentally.

physics.optics↗

arXiv2006

A polarized beam splitter using an anisotropic medium slab

The propagation of electromagnetic waves in the anisotropic medium with a single-sheeted hyperboloid dispersion relation is investigated. It is found that in such an anisotropic medium E- and H-polarized waves have the same dispersion relation, while E- and H-polarized waves exhibit opposite amphoteric refraction characteristics. E- (or H-) polarized waves are positively refracted whereas H- (or E-) polarized waves are negatively refracted at the interface associated with the anisotropic medium. By suitably using the properties of anomalous refraction in the anisotropic medium it is possible to realize a very simple and very efficient beam splitter to route the light. It is shown that the splitting angle and the splitting distance between E- and H- polarized beam is the function of anisotropic parameters, incident angle and slab thickness.

physics.optics↗

arXiv2006

Focusing and phase compensation of paraxial beams by a left-handed material slab

On the basis of angular spectrum representation, a formalism describing paraxial beams propagating through an isotropic left-handed material (LHM) slab is presented. The treatment allows us to introduce the ideas of beam focusing and phase compensation by LHM slab. Because of the negative refractive index of LHM slab, the inverse Gouy phase shift and the negative Rayleigh length of paraxial Gaussian beam are proposed. It is shown that the phase difference caused by the Gouy phase shift in right-handed material (RHM) can be compensated by that caused by the inverse Gouy phase shift in LHM. If certain matching conditions are satisfied, the intensity and phase distributions at object plane can be completely reconstructed at the image plane.

physics.optics↗

arXiv2006

Anomalous propagations of electromagnetic waves in anisotropic media with a unique dispersion relation

We investigate the reflection and refraction behaviors of electromagnetic waves at the interface between an isotropic material and the anisotropic medium with a unique dispersion relation. We show that the refraction angle of whether phase or energy flow for $E$-polarized waves is opposite to that for $H$-polarized waves, though the dispersion relations for $E$- and $H$-polarized waves are the same in such anisotropic media. For a certain polarized wave the refraction behaviors of wave vector and energy flow are also significantly different. It is found that waves exhibit different propagation behaviors in anisotropic media with different sign combinations of the permittivity and permeability tensors. Some interesting properties of propagation are also found in the special anisotropic media, such as amphoteric refraction, oblique total transmission for both $E$- and $H$-polarized waves, and the inversion of critical angle. The special anisotropic media can be realized by metamaterials and lead to potential applications, such as to fabricate polarization splitters with higher efficiencies than conventional counterparts.

physics.optics↗