Abstract-In this paper we have theoretically studied the omnidirectional total reflection frequency range of a multilayered dielectric heterostructures. Three structures of Na 3 AlF 6 /Ge multilayer have been studied. The thickness of the two layers of the first and second structure is differing from each other and the third photonic structure is the combination of first and second structures. Using the Transfer Matrix Method (TMM) and the Bloch theorem, the reflectivity of one dimensional periodic structure for TE-and TM-modes at different angles of incidence is calculated. From the analysis it is found that the proposed structure has very wide range of omnidirectional total frequency bands for both polarizations.

Abstract-It is well known that under certain conditions, one dimensional photonic crystal (1D-PC) displays total omni-directional reflection (ODR) band gaps. The enhancement of total omnidirectional reflection band gap in 1D-PC is calculated theoretically. Using Transfer Matrix Method (TMM) and Bloch theorem, the reflectivity of one dimensional periodic structure for TE and TM-modes at different angles of incidence has been calculated.

Abstract-In this paper a new type of optical filter using photonic band gap materials has been suggested. A detailed mathematical analysis is presented to predict allowed and forbidden bands of wavelengths with variation of angle of incidence. It is possible to get desired ranges of the electromagnetic spectrum filtered with this structure by changing the incidence angle of light.

Abstract-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.

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