The Electromagnetic Properties Of Left-handed Materials

Based on the classical electromagnetic theory, the electromagnetic characteristics of the left-handed materials have been studied. The left-handed material is a kind of artificial composite material. Owing to the negative dielectric permittivityεand the negative magnetic permeabilityμin some frequency range, to compare with the normal material, it has many unusual electromagnetic properties. So, this kind of material has great applications in many areas.The left-handed material, which is made in the laboratory, has the cyclical unit structure. This thesis demonstrates that the structure can show the negative dielectric permittivityεand the negative magnetic permeabilityμwhen the frequency of the incident electromagnetic wave is in a certain range. Since both of the dielectric permittivity and the magnetic permeability are negative, the left-handed material will have the negative refraction phenomenon and a series of odd electromagnetic effects such as the reversed Doppler shift, abnormal Cherenkov radiation, perfect lens, etc. The thesis discusses some of them and their applications theoretically.This thesis has studied the reflection and the refraction for an incident electromagnetic waves at the interface between the right-handed and the left-handed materials. The characteristics of evanescent wave of the total reflection were discussed. The experimental possibility of observing interference fringes of evanescent waves is proposed.And the distribution of interference fringes is calculated.For the interface between the right-handed material and the left-handed material, the reflection wave and the refraction wave are also part polarization lights. But when the reflection light becomes the total polarization light, there are two kinds of cases,in which the direction of the polarization of reflection light parallel to the incident plane or perpendicular to the incident plane. And there are two Brewster angles which correspond to the two cases respectively. The relationship between dielectric permittivity and magnetic permeability decides which case may occur.Also, we focus on the electromagnetic characteristics of the uniaxially anisotropic left-handed materials. The propagation of electromagnetic wave in uniaxially anisotropic left-handed material has to be in a certain space. it is to say, the angle between wave vector and optical axis must meet a certain condition. At the interface between the uniaxially anisotropic left-handed material and the normal material, an odd total reflection can happen under the condition of the incident wave angle smaller than the critical angle.When the electromagnetic wave incidents from the normal medium to the uniaxially anisotropic left-handed medium, the polarization phenomenon is also very special. Its Brewster angle is more complicated. In addition to the parameters of the medium, it is dependent on the frequency of incident wave. It is shown that the characteristics of electromagnetic wave propagation in uniaxially anisotropic left-handed media are significantly different from that in the isotropic left-handed media or the normal media.