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A binary superconductor–dielectric photonic crystal (PC) is proposed. The PC has the structure (AB)N with layer A representing the superconducting layer and layer B the dielectric material. The transfer matrix technique is used to deduce the transmission coefficient through the PC. The properties of photonic bandgaps (PBGs) arising in the transmission spectra are studied with the angle of incidence and with all parameters of the superconductor such as thickness, London penetration length, and critical temperature. Many interesting findings were reached: The PBG width decreases with increasing the incidence angle until it disappears for high incidence angles. There is an optimum superconducting layer thickness at which the PBG shows a maximum. The critical temperature has the lowest effect on the PBG width among the superconductor parameters, whereas London penetration length has the topmost effect.

Inserting of any sort of irregularity in a photonic crystal (PC) with a perfect periodicity can produce defect modes. Great interest has been directed towards defect modes due to many potential applications. In this work, a binary PC consisting of silica (SiO2) and silver (Ag) is assumed. The PC is supposed to have a mirror symmetry with the structure (SiO2/Ag)N(Ag/SiO2) N, where 2 N is the number of periods of the PC. The transmission spectra of the PC are investigated in the visible and IR wavelengths. It is found that when the thickness of Ag layer increases, band gaps are broadened, more band gaps appear starting at low wavelengths and all these band gaps are shifted toward loner wavelengths. Defect modes appear at certain thicknesses of Ag, diminish gradually and then entirely disappear. When the incidence angle increases, band gaps are blue shifted in contrary to their behavior with the increase of the thickness of the metal and SiO2 layers. Inserting of any sort of irregularity in a photonic crystal (PC) with a perfect periodicity can produce defect modes. Great interest has been directed towards defect modes due to many potential applications. In this work, a binary PC consisting of silica (SiO2) and silver (Ag) is assumed. The PC is supposed to have a mirror symmetry with the structure (SiO2/Ag)N(Ag/SiO2) N, where 2 N is the number of periods of the PC. The transmission spectra of the PC are investigated in the visible and IR wavelengths. It is found that when the thickness of Ag layer increases, band gaps are broadened, more band gaps appear starting at low wavelengths and all these band gaps are shifted toward loner wavelengths. Defect modes appear at certain thicknesses of Ag, diminish gradually and then entirely disappear. When the incidence angle increases, band gaps are blue shifted in contrary to their behavior with the increase of the thickness of the metal and SiO2 layers.

"A four-layer slab waveguide is treated analytically for optical sensing purposes. The layers of the waveguide are substrate, thin flm and cladding. Another layer is introduced between the substrate and the flm which is considered to have a negative permittivity or simultaneously negative permittivity (ε) and permeability (μ). The structure is analyzed and the refectance is deduced. The refectance of p-polarized (TM) incident wave is investigated and plotted. A peak is observed in the refectance profle which can be employed for sensing purposes. The refectance peak is optimized to give the optimum parameters corresponding to the sharpest peak. The performances of the structures as optical sensors are examined and compared." "A four-layer slab waveguide is treated analytically for optical sensing purposes. The layers of the waveguide are substrate, thin flm and cladding. Another layer is introduced between the substrate and the flm which is considered to have a negative permittivity or simultaneously negative permittivity (ε) and permeability (μ). The structure is analyzed and the refectance is deduced. The refectance of p-polarized (TM) incident wave is investigated and plotted. A peak is observed in the refectance profle which can be employed for sensing purposes. The refectance peak is optimized to give the optimum parameters corresponding to the sharpest peak. The performances of the structures as optical sensors are examined and compared."

" In a recent study, the authors proposed an optical broadband angular reflector having a band selective feature and high reflectivity rate for possible applications in photovoltaic applications using a binary photonic crystal. The obtained 100% reflectivity regions for TE and TM modes were in bandwidths of 244 nm and 134 nm, respectively. In this paper, we show theoretically the enhancement of the omnidirectional total-reflection wavelength range by using a ternary pho- tonic crystal. By introducing a 30 nm-layer of Si3N4 between every two layers, constituting a period of the lattice, the regions of 100% reflectivity for TE and TM modes are improved to bandwidths of 269.641 nm and 155.364 nm, respectively. The improvement in the omnidirectional region is about 16%." " In a recent study, the authors proposed an optical broadband angular reflector having a band selective feature and high reflectivity rate for possible applications in photovoltaic applications using a binary photonic crystal. The obtained 100% reflectivity regions for TE and TM modes were in bandwidths of 244 nm and 134 nm, respectively. In this paper, we show theoretically the enhancement of the omnidirectional total-reflection wavelength range by using a ternary pho- tonic crystal. By introducing a 30 nm-layer of Si3N4 between every two layers, constituting a period of the lattice, the regions of 100% reflectivity for TE and TM modes are improved to bandwidths of 269.641 nm and 155.364 nm, respectively. The improvement in the omnidirectional region is about 16%."

" A photonic crystal (PC) having the structure (AB)NA is investigated. A and B are superconductor and dielectric layers, respectively. P-polarized (TM) wave is assumed to be incident on the PC. The transmission of TM waves through the PC is studied with a focus on photonic band gap (PBG). The change in the PBG is studied with the variation of different parameters of the super- conducting layer such as temperature, critical temperature, thickness and London penetration length. The angle of incidence dependence of the PBG is also investigated. The PBG band width at half maximum (BWHM) decreases with increasing the incidence angle until Brewster angle is reached where the band gap vanishes. The BWHM has shown the lowest dependence on temperature and critical temperature among the parameters of the superconducting layer. London penetration length has the greatest effect on the BWHM among the parameters of the super- conductor layer." " A photonic crystal (PC) having the structure (AB)NA is investigated. A and B are superconductor and dielectric layers, respectively. P-polarized (TM) wave is assumed to be incident on the PC. The transmission of TM waves through the PC is studied with a focus on photonic band gap (PBG). The change in the PBG is studied with the variation of different parameters of the super- conducting layer such as temperature, critical temperature, thickness and London penetration length. The angle of incidence dependence of the PBG is also investigated. The PBG band width at half maximum (BWHM) decreases with increasing the incidence angle until Brewster angle is reached where the band gap vanishes. The BWHM has shown the lowest dependence on temperature and critical temperature among the parameters of the superconducting layer. London penetration length has the greatest effect on the BWHM among the parameters of the super- conductor layer."

In this paper, a four-layer slab waveguide sensor is proposed. The waveguide has the conventional structure of a substrate, a guiding film and a cladding. At the substrate-film interface, an additional layer is inserted which can be a material with negative permeability or a material with simultaneously negative permittivity and permeability. The proposed waveguide is analyzed and both the dispersion relation and Fresnel coefficients are derived. The reflectance of an incident wave from the structure is investigated and plotted. The reflectance dip appearing in the profile is optimized. Using the two structures as optical sensor is also studied. The حerformance of the two structures as optical sensors is compared. In this paper, a four-layer slab waveguide sensor is proposed. The waveguide has the conventional structure of a substrate, a guiding film and a cladding. At the substrate-film interface, an additional layer is inserted which can be a material with negative permeability or a material with simultaneously negative permittivity and permeability. The proposed waveguide is analyzed and both the dispersion relation and Fresnel coefficients are derived. The reflectance of an incident wave from the structure is investigated and plotted. The reflectance dip appearing in the profile is optimized. Using the two structures as optical sensor is also studied. The حerformance of the two structures as optical sensors is compared.