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1
Content available remote Ternary photonic crystal with left-handed material layer for refractometric application
Taya S. A.
Opto-Electronics Review
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2018
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Vol. 26, No. 3
236--241
EN
A ternary photonic crystal with left-handed material (LHM) layer is examined for refractometric applications. One of the layers is assumed to be air and treated as an analyte. The transmittance from the ternary photonic crystal is studied in details and the wavelength shift due to the change in the refractive index of the analyte is investigated. The transmittance is investigated with the parameters of the LHM. It is found that the wavelength shift can be significantly enhanced with the decrease of both real part of the LHM permittivity and thickness.
2
Content available Phase and group velocities of surface waves in left-handed material waveguide structures
Taya S. A., Elwasife K. Y., Qadoura I. M.
Optica Applicata
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2017
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Vol. 47, nr 2
307--318
EN
We assume a three-layer waveguide structure consisting of a dielectric core layer embedded between two left-handed material claddings. The phase and group velocities of surface waves supported by the waveguide structure are investigated. Many interesting features were observed such as normal dispersion behavior in which the effective index increases with the increase in the propagating wave frequency. The phase velocity shows a strong dependence on the wave frequency and decreases with increasing the frequency. It can be enhanced with the increase in the guiding layer thickness. The group velocity peaks at some value of the normalized frequency and then decays.
3
Content available remote Reflection and transmission from left-handed material structures using Lorentz and Drude medium models
Taya S. A., El-Amassi D. M.
Opto-Electronics Review
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2015
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Vol. 23, No. 3
214-221
EN
The present article investigates theoretically the refection and transmission through a lossless dielectric slab embedded between two semi-infinite left-handed materials (LHMs) in which the electric permittivity and magnetic permeability are simultaneously negative. The LHM is assumed to be dispersive according to Lorentz as well as Drude medium model. The reflection and transmission coefficients are studied with the angle of incidence, frequency and slab thickness. The effect of the damping frequency is also investigated. It is found that the damping frequency has an insignificant effect on reflected, transmitted and loss powers. Band pass filter is one of the possible applications of the proposed structure.
4
Content available Theoretical investigation of slab waveguide sensor using anisotropic metamaterial
Taya S. A.
Optica Applicata
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2015
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Vol. 45, nr 3
405--417
EN
A three-layer slab waveguide with air as a substrate, lossless dielectric as a guiding film, and anisotropic double negative material as a cladding is explored as an optical sensor for refractometry applications. The double negative material is assumed to have a negative electric permittivity and magnetic permeability only along the wave propagation direction. The sensitivity of a guided mode to the variation in the refractive index of air substrate is derived and studied for the first few guided modes. It is found that the sensitivity can be enhanced with decreasing the guided light frequency as well as the film thickness. The sensitivity can reach 100% for some waveguide configurations.
5
Content available remote Slab waveguide with air core layer and anisotropic left-handed material claddings as a sensor
Taya S. A.
Opto-Electronics Review
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2014
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Vol. 22, No. 4
252-257
EN
A three-layer slab waveguide with air core layer and anisotropic left-handed material claddings is investigated for sensing applications. Different from the waveguide mode sensors and surface plasmon resonance sensors in which the analyte is placed in the evanescent field region, the proposed sensor contains the sample in the core region that supports the oscillating field. Due to the strong concentration of the electromagnetic field in the analyte medium, the proposed device exhibits unusual sensitivity enhancement. The simulations revealed that the sensitivity improvement of TE3 mode compared to conventional evanescent wave sensor is approximately a factor of 20.
6
Content available Dye-sensitized solar cells using some organic dyes as photosensitizers
El-Agez T. M., Taya S. A., Elrefi K S, Abdel-Latif M S
Optica Applicata
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2014
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Vol. 44, nr 2
345--351
EN
Eight organic dyes are used as sensitizers for dye-sensitized solar cells. These dyes are eosin Y, aniline blue, bromophenol blue, alcian blue, methyl orange, crystal violet, fast green, and carbol fuchsin. The absorption spectra of these dyes are carried out by UV–VIS spectrophotometry. Dye-sensitized solar cells are assembled using nanostructured, mesoporous TiO2 films. Photovoltaic parameters of the fabricated cells are investigated and the highest overall conversion efficiency of 0.399% is obtained for the dye-sensitized solar cell sensitized with eosin Y.
7
Content available remote Dye-sensitized solar cells with natural dyes extracted from plant seeds
El-Ghamri H S, El-Agez T. M., Taya S. A., Abdel-Latif M S, Batniji A Y
Materials Science Poland
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2014
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Vol. 32, No. 4
547--554
EN
The application of natural dyes extracted from plant seeds in the fabrication of dye-sensitized solar cells (DSSCs) has been explored. Ten dyes were extracted from different plant seeds and used as sensitizers for DSSCs. The dyes were characterized using UV-Vis spectrophotometry. DSSCs were prepared using TiO2 and ZnO nanostructured mesoporous films. The highest conversion efficiency of 0.875 % was obtained with an allium cepa (onion) extract-sensitized TiO2 solar cell. The process of TiO2-film sintering was studied and it was found that the sintering procedure significantly affects the response of the cell. The short circuit current of the DSSC was found to be considerably enhanced when the TiO2 semiconducting layer was sintered gradually.
8
Content available remote Theoretical study of slab waveguide optical sensor with left-handed material as a core layer
Taya S. A., El-Agez T. M., Kullab H. M., Abadla M. M., Shabat M. M.
Optica Applicata
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2012
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Vol. 42, nr 1
193-205
EN
A three-layer planar waveguide sensor consisting of thin left-handed material core layer is investigated for sensing applications. The sensitivity of the proposed sensor to the changes in the refractive index of the cladding is presented and studied for TE-polarized light. It is observed that the sensitivity of the proposed sensor is improved compared to that of the conventional three-layer slab waveguide sensor. It is also found that the sensitivity of the structure proposed is negative and critically dependent on the dispersive permittivity and permeability of the core layer.
9
Content available remote Lossy double negative guiding layer optical sensors
El-Khozondar H. J., Taya S. A., Shabat M. M., Mehjez E. M.
Opto-Electronics Review
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2011
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Vol. 19, No. 3
277-281
EN
We proposed a three-layer waveguide as an optical sensor for homogeneous sensing applications. A guiding layer of the proposed structure is considered as lossy left-handed material (LHM) with simultaneously the complex negative electric permittivity µ and the complex negative magnetic permeability µ. We also assume a cladding layer to have an intensity-dependent refractive index. Sensitivity of the proposed optical waveguide sensor is derived and its dependence on different parameters of a waveguide is studied.
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