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Wyszukujesz frazę "crystals" wg kryterium: Temat


Wyświetlanie 1-12 z 12
Tytuł:
Telecommunication filter based on the symmetrical photonic crystal Bg5/Cu1/Bg5
Autorzy:
Baraket, Z.
Zaghdoudi, J.
Kanzari, M.
Powiązania:
https://bibliotekanauki.pl/articles/175028.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
symmetry
telecommunication
photonic crystals
Opis:
Thanks to the transfer matrix method, we perform a theoretical investigation of the optical properties of the symmetrical photonic crystal designed as Bg5/Cu1/Bg5, where Cu1 is the first generation of the copper mean sequence and Bg5 is the fifth generation of the Bragg sequence. We design a developed polychromatic filter which allows the transmission of all the telecommunication wavelengths 0.85, 1.3, and 1.55 µm at oblique incidence for both of TE and TM polarization with a high transmission rate and high quality factor. This photonic crystal can be employed in the fabrication of telecommunication devices.
Źródło:
Optica Applicata; 2018, 48, 3; 361-371
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of the symmetrical deformation y = xk + 1 on the optimization of the symmetrical multiple channeled white light color filter
Autorzy:
Baraket, Z.
Zaghdoudi, J.
Kanzari, M.
Powiązania:
https://bibliotekanauki.pl/articles/173545.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
photonic crystals
symmetry
filter
polarization
optimization
Opis:
In this paper, we consider a hybrid photonic crystal symmetrically deformed (Bg5/Cu3/Bg5) consisting of the third generation of the copper mean sequence (Cu3), sandwiched between two Bragg mirrors at the fifth generation (Bg5). Our system realizes a polychromatic filter that transmits five wavelengths in the visible spectrum independently of the polarization of the light transverse electric or transverse magnetic. Secondly, the photonic crystal (Bg5/Cu3/Bg5) undergoes the deformation y = xk + 1 (where k is the degree of deformation, x and y are respectively the coordinates of the system before and after the deformation). With a proper choice of the degree of deformation k, this photonic crystal maintains its property of polychromatic filter whose transmission wavelength is independent of the polarization’s state. Thanks to this deformation, we can disperse the optical windows in different spectra of visible light and exactly in the violet, blue, green, and orange light. This system can be used in the fabrication of color filter devices and the white light emitting diodes.
Źródło:
Optica Applicata; 2017, 47, 1; 19-28
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Colloidal crystal cladded microfiber for refractive index sensing
Autorzy:
Yan, H. T.
Zhao, X Y
Zhang, Ch.
Zhen, Z Q
Li, Q Z
Cao, J X
Xia, L X
Powiązania:
https://bibliotekanauki.pl/articles/174902.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
microfibers
colloidal crystals
refractive index sensing
Opis:
We investigate the evanescent field of a microfiber wrapped by colloidal crystals. The microfiber has the diameter of about 1 μm that is drawn from a single-mode fiber with an alcohol lamp. The colloidal spheres are further attached to the microfiber through thermal evaporation, then they self-assemble to crystal-like structures. The 400 nm, 590 nm, and 710 nm-diameter SiO2 colloidal spheres are used, respectively. The spectral responses are studied theoretically and experimentally, and the results agree with each other. It is revealed that the evanescent field of a microfiber could be modulated by the photonic band-gap of colloidal crystals. This characteristic is very useful in refractive index sensing for liquids.
Źródło:
Optica Applicata; 2014, 44, 2; 309-315
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Defect modes properties in one-dimensional photonic crystals employing a superconducting nanocomposite material
Autorzy:
Aly, A. H.
Elsayed, H. A.
Malek, C.
Powiązania:
https://bibliotekanauki.pl/articles/173888.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
photonic crystals
band gap
defect mode
nanocomposite
Opis:
In the present work, we investigate theoretically the transmission characteristics of one-dimensional photonic crystals that contain a defect layer of a nanocomposite material in infrared radiation. The theoretical treatment is obtained depending on the fundamentals of the characteristic matrix method. Here, the nanocomposite designed from nanoparticles of a superconducting material is arranged into a dielectric medium. The numerical results clarify the acute effect of the volume fraction and the operating temperature on the effective permittivity of the nanocomposite material. Therefore, the volume fraction, the operating temperature and other parameters such as the permittivity of the dielectric material and the threshold frequency could have a significant effect on the characteristics of the defect modes. Thus, our structure may be very promising in many applications such as narrow band filters and among optoelectronic applications.
Źródło:
Optica Applicata; 2018, 48, 1; 53-64
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photonic band gap in negative ternary refractive indices of two-dimensional photonic crystal
Autorzy:
Gharaati, A
Mohamadebrahimi, L
Roozitalab, Z
Powiązania:
https://bibliotekanauki.pl/articles/174931.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
negative refraction
two dimensional photonic crystals
metamaterials
band gaps
Opis:
In this paper, we study propagation of electromagnetic wave in negative ternary refractive indices of two-dimensional photonic crystals. We consider two structures with two concentric cylindrical rod and shell in which one of them has negative refractive indices, in positive dielectric background. It is shown that by increasing the diameter of the rod in both structures, we can obtain more and wider band gaps in comparison with the structures in which there is no negative refractive index materials. This increase is more considerable in the first structure, in which the rod has a negative refractive index, in comparison with the second one, where the rod has a positive refractive index.
Źródło:
Optica Applicata; 2014, 44, 4; 637-648
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coloring of radiation scattered by polymer-dispersed liquid crystals
Autorzy:
Maksimyak, P.
Maksimyak, A
Nehrych, A
Powiązania:
https://bibliotekanauki.pl/articles/173821.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
polymer-dispersed liquid crystals
coloring effect
scattering
spatial frequency filtering
Opis:
We analyze the effects of coloring of a beam traversing a light-scattering medium. Spectral investigation of the effects of coloring has been carried out using a solution of liquid crystal in a polymer matrix (polymer-dispersed liquid crystals – PDLC). It is shown that the result of coloring of the beam at the output of the medium depends on the magnitudes of the phase delays of the singly forward scattered partial signals. We consider the influence of interference coloring effect on the transmission scattering and spatial-frequency filtering of the radiation which has passed through the PDLC.
Źródło:
Optica Applicata; 2014, 44, 4; 545-554
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of thermal tunable multichannel filter using defective metallic photonic crystals
Autorzy:
Gharaati, A.
Zare, Z.
Powiązania:
https://bibliotekanauki.pl/articles/174165.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
photonic crystals
temperature dependent refractive index
multichannel filter
defective mode
Opis:
The transmission spectra of one dimensional metallic photonic crystal containing defects are studied using a transfer matrix method. We consider silver as a defect layer with a refractive index dependent on wavelength and temperature simultaneously. Since the loss factor of silver is the function of temperature, we should find a structure that has sharp transmission peaks to model a filter. We present the structure with a coupled defect. It is found that the number of transmission resonant peaks is equal to the number of coupled defects and they are tunable with temperature and incident angle.
Źródło:
Optica Applicata; 2017, 47, 4; 611-619
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computer simulation and modeling of solar energy based on photonic band gap materials
Autorzy:
Aly, A. H.
Sayed, H.
Powiązania:
https://bibliotekanauki.pl/articles/174792.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
photovoltaic
thermal energy
renewable energy
photonic crystals
anti-reflection coating
Opis:
In this paper, we have obtained theoretically a convenient way to improve the tandem solar cell efficiency by using one-dimensional binary photonic crystals in the anti-reflection coating and intermediate reflective layer. Also, we design and simulate our structure by using two different methods; MATLAB program based on a transfer matrix method and COMSOL Multiphysics software based on a finite element method. We have obtained the localization of the photons energy on the appropriate cell and then reduced the energy losses by controlling the photonic band gap. The present design is more convenient for cold countries.
Źródło:
Optica Applicata; 2018, 48, 1; 117-126
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimizing of the piezo-optic interaction geometry in SrB4O7 crystals
Autorzy:
Buryy, O.
Demyanyshyn, N.
Mytsyk, B.
Andrushchak, A.
Powiązania:
https://bibliotekanauki.pl/articles/174724.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
piezo-optical effect
optical path
path difference
SrB4O7 crystals
Opis:
The optimal geometries of the piezo-optic interaction are determined for SrB4O7 crystals by the extreme surfaces method. The goal functions of optimization are the change of optical path length and optical path difference, normalized on mechanical stress and crystal thickness, and the parameters of optimization are the spherical angles determining the directions of the light beam propagation and the uniaxial pressure action. It is shown that the maximal changes of optical path length for the orthogonal polarized waves are equal to 2.09 or 1.65 B (1 B = 1 brewster = 10–12 m2/N) and the maximal change of optical path difference is equal to 2.22 B respectively in transversal geometry of the piezo-optic interaction (for λ =633nm and T =20ºC).
Źródło:
Optica Applicata; 2016, 46, 3; 447-459
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a novel photonic crystal 1.31/1.55 µm bi-band filter for near infrared application
Autorzy:
Lallam, F.
Badaoui, H.
Abri, M.
Fedaouche, A.
Powiązania:
https://bibliotekanauki.pl/articles/173714.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
finite-difference time-domain
FDTD
photonic crystals
waveguide
W1KA
selective filters
Opis:
A novel design of a double selective filter for integrated optics in two-dimensional photonic crystals operating at a wavelength of 1.31 and 1.55 µm is proposed in this paper. We focus particularly on filters transmission and selectivity enhancement. The two-dimensional photonic crystals filters are simulated by using a combination of three cascaded waveguides; these later are conceived by one missing row and with different rods radii for efficient filtering purpose. The properties of these photonic crystal structures are numerically investigated by using the two-dimensional finite-difference time-domain method and the numerical results are given for incident light wave having transverse electrical polarization. A final synthesized filter topology is presented and the maximum of transmission is found around 70% and 60% localized respectively near 1.31 and 1.55 µm wavelengths.
Źródło:
Optica Applicata; 2018, 48, 3; 341-348
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance analysis of two-dimensional photonic crystal octagonal ring resonator based eight channel demultiplexer
Autorzy:
Kannaiyan, V.
Dhamodharan, S. K.
Savarimuthu, R.
Powiązania:
https://bibliotekanauki.pl/articles/174789.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
two-dimensional photonic crystals
photonic band gap
ring resonator
waveguide
demultiplexer
wavelength division multiplexing
Opis:
We proposed a high performance eight channel demultiplexer using two-dimensional photonic crystal octagonal ring resonator for wavelength division multiplexing applications. The performance parameters such as transmission efficiency, Q factor, spectral width, resonant wavelength, crosstalk and channel spacing of the proposed demultiplexers are evaluated. The plane wave expansion method manipulates photonic band gap of periodic and non-periodic structure. Finite-difference time-domain method is used to evaluate the performance parameters of designed two-dimensional photonic crystal structure. The proposed demultiplexer provides overall transmission efficiency, Q factor, spectral width of about 98%, 1968 and 0.8 nm, respectively. The ultra-compact eight channel demultiplexer performs better than the reported one. Hence this work can be implemented for real time applications.
Źródło:
Optica Applicata; 2017, 47, 1; 7-18
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron paramagnetic resonance studies of manganese and cobalt ions in YAlO3 crystals
Autorzy:
Stefaniuk, I.
Rogalska, I
Suchocki, A
Berkowski, M.
Cieniek, B.
Potera, P.
Powiązania:
https://bibliotekanauki.pl/articles/174068.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electron paramagnetic resonance (EPR)
spin Hamiltonian
Mn2+
Mn4+
Co2+
Fe3+
Cr3+
Nd3+ and Er3+ ions
YAlO3 (YAP) crystals
Opis:
The results of X-band electron paramagnetic resonance measurements of Mn2+ and Mn4+ ions in YAlO3 (YAP) crystals in the temperature range 100–300 K are presented. Additionally, we observe electron paramagnetic resonance spectra of unintentional impurities Fe3+ and Cr3+ in YAP crystals. The angular dependence for Mn ions in YAP crystals can be presented. We aim at obtaining a better insight into the spectroscopic properties of paramagnetic Mn centers and structural information about their nearest environment in YAP host and at determining the valence of manganese ion. In this paper we compare electron paramagnetic resonance spectra for Co and Mn ions in YAP crystals.
Źródło:
Optica Applicata; 2014, 44, 1; 113-121
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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