NEGATIVE REFRACTION BY PHOTONIC CRYSTAL

—Negative refraction has been the subject of considerable interest and it may,provide the possibility of a variety of novel applications. It arises in metamaterials that have simultaneous negative permittivity ε and permeability µ, where in-homogeneities are much smaller than the wavelength of the incoming radiation. Recently it has been shown that photonic crystals (PCs) may,also exhibit negative refraction although they have a periodically modulated positive permittivity ε and permeability µ. We have theoretically studied the negative refraction in one-dimensional (1D) photonic crystals (PCs) consisting dielectric ZnSe with air. By using transfer matrix method and block theorem we have studied the photonic band structure and group velocity and with the help of group velocity we have obtained the frequency bands of negative refraction. We found that negative refraction may occur near the low frequency edge of the second and fourth bandgaps. We have also studied the effective index of refraction and the transverse position shift through PC that can characterize negative refraction more explicitly.