Goos-Hanchen shift of the reflected wave through an anisotropic metamaterial containing metal/dielectric nanocomposites

摘要

Goos-Hanchen (GH) shift of a transverse-magnetic (TM) wave reflected from a semi-infinite anisotropic metamaterial consisting of aligned metallic nanowires in a dielectric matrix is investigated. Based on Bruggeman effective medium theory, we obtain the conditions for realizing the negative refraction, which are dependent on both the incident wavelength and the volume fraction of metallic inclusions. Then, we investigate the GH shifts from the composite metamaterial with positive and negative refractions with the stationary-phase method. Numerical results show that the enhancement of GH shift can be achieved near the pseudo-Brewster angle for small volume fractions and at the close-to-grazing incidence for large volume fractions. We further find that for positively refractive metamaterials with weak absorption, one can realize the transition from negative GH shift to the positive one by adjusting the incident wavelength. However, for negatively refractive composite metamaterials, the reversal of the GH shifts may take place by the adjustment of the volume fraction instead of the incident wavelength. In order to demonstrate the validity of the stationary-phase approach, numerical simulations are performed for a Gaussian-shaped beam. In the end, by using COMSOL simulation, a comprehensive understanding is given and the above analysis is confirmed.