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Wyszukujesz frazę "42.70.Df" wg kryterium: Temat


Tytuł:
Design of Pressure Sensor Based on Two-Dimensional Photonic Crystal
Autorzy:
Zouache, T.
Hocini, A.
Harhouz, A.
Mokhtari, R.
Powiązania:
https://bibliotekanauki.pl/articles/1033334.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Qs
78.67.Pt
07.07.Df
42.79.-e
Opis:
In this work, we design a new pressure sensor based on two-dimensional photonic crystal waveguide coupled to a point-defect resonant microcavity. The mechanism of sensing is based on the change of the germanium refractive index as function of the hydrostatic pressure P. The resonant wavelength will shift when pressure variation induces change in the refractive indexes of the structure. The pressure variation causes the shifting of defect modes. The properties of the refractive index sensor are simulated using the finite-difference time-domain algorithm and the plane wave expansion method. These kinds of sensors have many advantages in compactness, high sensitivity, and various choices of materials.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 68-70
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photonic Liquid Crystal Fibers with Polymers
Autorzy:
Woliński, T.
Tefelska, M.
Mileńko, K.
Siarkowska, A.
Budaszewski, D.
Domański, A.
Ertman, S.
Orzechowski, K.
Rutkowska, K.
Sierakowski, M.
Nowinowski-Kruszelnicki, E.
Dąbrowski, R.
Mergo, P.
Powiązania:
https://bibliotekanauki.pl/articles/1399416.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.81.Wg
02.60.Cb
42.70.Qs
Opis:
Photonic liquid crystal fibers with polymers constitute a new solution based on liquid crystals and microstructured polymer optical fibers opening up new areas in innovative sensing and photonic devices applications. Compared with their silica-based microstructured fibers, it is easier to fabricate exotic microstructured polymer optical fibers by extrusion or drilling at low temperature; their nonlinearity is potentially stronger, the range of available polymers that may be drawn is more diverse and the biocompatibility of polymers is often better. Liquid crystals due to their attractive properties i.e., the high birefringence, high electro-optic and thermo-optic effects are a very good candidate for microstructured polymer optical fiber infiltration to obtain tunable all-in-fiber innovative photonic devices. The paper will discuss basic properties and possible applications of the polymer photonic liquid crystal fibers that will arise from their high optical tunability with external and internal factors. Current research effort is directed towards two main solutions: photonic crystal fibers and microstructured polymer optical fiber-based structures, both infiltrated with liquid crystals of tailored optical properties.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 613-616
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prenematic Self-Assembling of Mesogenic Molecules in Isotropic Liquid and Orientational Order in Nematic Phase
Autorzy:
Wolarz, E.
Bauman, D.
Jadżyn, J.
Dąbrowski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1493609.pdf
Data publikacji:
2011-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
61.30.Gd
77.22.Ch
Opis:
Dielectric relaxation study of nematogenic 4-n-alkyl-4'-cyanobiphenyls (nCB, n = 5, 6), 4-(trans-4'-n-alkylcyclohexyl)isothiocyanatobenzenes (nCHBT, n = 6, 8), 4-cyanophenyl-4'-n-alkylbenzoates (nCPB, n = 6, 8), 4-cyano-3-fluorophenyl-4'-n-octyloxybenzoate (8OCFPB), and 4-cyanophenyl-4'-n-octyloxy-3'-fluorobenzoate (8OCPFB) was performed in the frequency range from 50 kHz to 100 MHz in the nematic and isotropic phases. The static permittivity and the relaxation process related to the rotation of molecules around their short axis was analyzed. For some of these liquid crystals anomalous temperature dependence of static permittivity in the pretransitional region of the isotropic phase was observed. Based on the Meier-Saupe-Martin model of molecular diffusion in nematics, the orientational order parameter 〈$P_2$〉 was determined from dielectric relaxation times and retardation factor. The values of 〈$P_2$〉 calculated from the dielectric relaxation data were compared with the results obtained from measurements of polarized electronic absorption. Correlations between the magnitude of the dielectric pretransitional effect and the orientational order in the nematic phase were discussed.
Źródło:
Acta Physica Polonica A; 2011, 120, 3; 447-454
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitive Films for Optical Detection of Ammonia and Nitrogen Dioxide
Autorzy:
Tyszkiewicz, C.
Karasiński, P.
Rogoziński, R.
Powiązania:
https://bibliotekanauki.pl/articles/1418064.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Fw
42.70.Ce
07.07.Df
Opis:
The sol-gel technology allows preparation of the thin silica films ranging in porosity from dense to highly porous. These films can function as matrix binding molecules of pH-sensitive indicators and can be utilized as sensitive coatings for intensity based planar evanescent wave chemical sensors. This paper is devoted to manufacturing technology and characterization of highly porous silica films deposited on soda-lime glass substrates, impregnated with bromocresole purple and cresole red. Two different methods of impregnation were used: dip coating, which entails sensitization of both silica films deposited on each side of a substrate and selective deposition of a dye solution on single side of the substrate. Manufactured sensitive films were tested toward influence of gaseous ammonia and nitrogen dioxide on their spectral characteristics of the absorption coefficient and the imaginary part of the refractive index. It was shown that bromocresole purple allows detection of both gases: $NH_3$ and $NO_2$.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 915-920
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sol-Gel Derived Sensitive Films for Ammonia Sensors
Autorzy:
Tyszkiewicz, C.
Karasiński, P.
Rogoziński, R.
Powiązania:
https://bibliotekanauki.pl/articles/1506869.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Fw
42.70.Ce
07.07.Df
Opis:
The sol-gel technology allows the preparation of silica thin films ranging in porosity from dense to highly porous films (50%). Porous silica films can function as a matrix that is able to bind the molecules of pH-sensitive indicators and therefore can be utilized as a sensitive film in construction of intensity based fibre or planar optical sensors for ammonia detection. We report the fabrication and characterization of ammonia sensitive, highly porous silica films deposited on soda-lime glass plates and doped with the bromocresole purple, and bromothymol blue molecules. In this paper we present the influence of the substrate withdrawal speed from sol on a thickness and a refractive index of the undoped silica films, as well as spectral absorbance characteristics of the doped films. An influence of ammonia concentration in air and relative humidity on a transmission of produced sensitive films is also presented.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1262-1266
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beam Propagation Method for Liquid Crystal-Core Optical Fiber Waveguides
Autorzy:
Szymańska, A.
Woliński, T.
Powiązania:
https://bibliotekanauki.pl/articles/2008241.pdf
Data publikacji:
1999-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.81.Qb
42.81.Dp
Opis:
Propagation effects in liquid crystal-core optical fiber waveguides were investigated and simulated by means of beam propagation method. Spatial propagation beam distribution for anisotropic liquid crystal fibers was defined by using BPM_CAD software package (courtesy of Optiwave Corporation). The field intensity was related to the refractive index of core at the liquid crystal fiber in two different waveguide configurations: planar and radial, whereas the number of the propagating modes was calculated. Numerical results were compared with some experimental data formerly obtained.
Źródło:
Acta Physica Polonica A; 1999, 95, 5; 761-766
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polarization Properties of Liquid-Crystal Elliptical-Core Fibers
Autorzy:
Szymańska, A.
Woliński, T. R.
Powiązania:
https://bibliotekanauki.pl/articles/2023965.pdf
Data publikacji:
2001-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.81.Qb
42.81.Dp
Opis:
Polarization properties of liquid-crystal core optical fibers have been investigated. The liquid-crystal fiber is characterized by elliptical anisotropic core with low birefringence liquid crystal introduced by capillary axis. The paper presents also initial experimental results of the liquid-crystal fiber in the polarimetric configuration subjected to the influence of selected perturbations.
Źródło:
Acta Physica Polonica A; 2001, 99, 1; 201-205
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beam Propagation in Nematic Liquid Crystals
Autorzy:
Strinic, A. I.
Belic, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047844.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Tg
42.65.Sf
42.70.Df
Opis:
We investigate the behavior of beams propagating in nematic liquid crystals. A spatiotemporal model for the beam propagation and the director reorientation in a nematic liquid crystal is treated numerically in three spatial dimensions and time. We demonstrate the formation of stable solitons in a narrow threshold region of beam intensities for a set of fixed parameters and display soliton breathing. Below the threshold region the beams diffract, above the region spatiotemporal instabilities are observed, as the input intensity and the optical and static permittivity anisotropies of the liquid crystal molecules are increased. We demonstrate the filamentation of solitons above the threshold with increasing input intensity.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 877-883
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Counterpropagating Dipole Beams in Nematic Liquid Crystals
Autorzy:
Strinic, A. I.
Jovic, D. M.
Belic, M. R.
Powiązania:
https://bibliotekanauki.pl/articles/2047845.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Tg
42.65.Sf
42.70.Df
Opis:
We investigate the behavior of counterpropagating optical beam structures in nematic liquid crystals. We restrict our attention to the dipole-dipole beam arrangements. A time-dependent model for the beam propagation and the director reorientation in nematic liquid crystals is numerically treated in three spatial dimensions and time. Stable dipole beams are observed in a very narrow threshold region of control parameters. Below this region the beams diffract, above the region spatiotemporal instabilities are observed, as the input intensity is increased and also as the distance between the dipole partners is decreased. A transverse beam displacement of counterpropagating dipole beams is also found. The difference between the in-phase and out-of-phase components of the dipole is significant, but only for a smaller distance between the dipole partners.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 885-890
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyper-Solitons in Nematic Liquid Crystals
Autorzy:
Strinic, A.
Petrović, M.
Belić, M.
Powiązania:
https://bibliotekanauki.pl/articles/1791208.pdf
Data publikacji:
2009-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.65.Tg
Opis:
We study laser light propagation in a cell containing a liquid crystal in the nematic phase. We launch hyper-Gaussian beams and follow their behavior within the cell, in time and in three spatial dimensions, utilizing an appropriately developed theoretical model and a numerical procedure based on the fast Fourier transform. We demonstrate the formation of stable "hyper-soliton" breathers in a narrow region of beam intensities, for fixed other parameters. Hyper-solitons are similar in appearance and behavior to the usual solitons, formed by launching the usual Gaussian beams; however noticeable differences persist.
Źródło:
Acta Physica Polonica A; 2009, 116, 4; 510-512
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Refractive Indices, Order Parameter and Optical Transmittance Studies of a Nematic Liquid Crystal Mixture
Autorzy:
Singh, A. K.
Manohar, R.
Shukla, J. P.
Biradar, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047089.pdf
Data publikacji:
2006-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.-v
42.70.Df
Opis:
Measurements of ordinary refractive index, birefringence, density, and order parameter were made on a technologically important nematogen and the data obtained for its nematic and isotropic phase were reported. A modified wedge method was used for the measurement of the birefringence (δ n). The nematic-isotropic phase transition temperature matches very well as is exhibited from the value of refractive indices and densities obtained using different techniques. The optical anisotropy and density data were used to determine the order parameter and principal polarizability of the nematic mixture using the Vuks approach and their temperature dependence was discussed. The macroscopic order parameter was obtained and compared with microscopic order parameter. These two values agree very well.
Źródło:
Acta Physica Polonica A; 2006, 110, 4; 485-493
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controlling Light by Light: Optical Modulation in Chiral Nematics
Autorzy:
Sierakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2008249.pdf
Data publikacji:
1999-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.-k
42.81.Wg
42.70.Df
Opis:
Nonlinear optics of chiral liquid-crystalline media have been in scope of our interest for several years. Our previous observations in the subject had already been reported. This paper discusses a possibility of utilising the nonlinear optical properties of liquid crystals for practical purposes. We discuss an idea of "in line" intensity measurements of laser beam. The idea is based on two optical phenomena which are observed in liquid-crystalline media possessing a periodically stratified structure: nonlinear optical effect and selective light reflection. The effects start to appear by activating light intensities of the order of MW/m$\text{}^{2}$, so the method can be potentially applied at present to high-intensity light beams (corresponding laser power is approximately 0.1 W), although there are now also prospects to lower this value significantly.
Źródło:
Acta Physica Polonica A; 1999, 95, 5; 777-782
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Full-Vectorial Description of the Light Guidance in Anisotropic Photonic Liquid Crystal Fibers
Autorzy:
Rutkowska, K.
Wei, L.
Powiązania:
https://bibliotekanauki.pl/articles/1418035.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.60.Cb
02.70.Bf
42.25.Bs
42.70.Qs
42.81.Wg
42.70.Df
Opis:
In this paper we present our theoretical approach for the description of the light guidance in photonic liquid crystal fibers. In particular, we focus on the numerical methods allowing for a full implementation of the liquid crystals properties (i.e., including their optical anisotropy and molecular orientation), with a final target in characterizing photonic liquid crystal fibers with accessible computational effort. For this purpose suitable analytical formulae required for a full-vectorial description of the optical modes in photonic liquid crystal fibers have been derived. In addition, computational schemes allowing for numerical implementation of theoretical formulations (with the use of the finite-difference scheme) have been developed, validated and optimized. Their numerical convergence has been checked for different structures, as well as for different input parameters (e.g., grid-size). Obtained results have been compared to those analytically calculated, known from literature and/or got with use of commercial software. Moreover, the implemented schemes have been examined in accordance with experimental tests performed on the photonic liquid crystal fiber of interest.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 880-890
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Inelastic Light Scattering in a Smectic Liquid Crystal
Autorzy:
Pura, B.
Jęda, W.
Zagórski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1968843.pdf
Data publikacji:
1998-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.df
42.65.-k
Opis:
Results of measurements of the intensity of light scattered by a smectic liquid crystal are reported for three phases of the specimen. A strong dependence of the scattered intensity on the relative directions of polarization vector and molecular orientation is observed. A mechanism of light interaction with material is proposed, it is attributed to brillouin - like scattering of light on director - system excitations.
Źródło:
Acta Physica Polonica A; 1998, 93, 3; 465-470
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular Dynamic of (4-(4Octylobiphenyl)carboxylan) 4-(2-methylobuthyl) phenol Liquid Crystal Having Blue Phase Seen via the Dielectric Spectroscopy Method
Autorzy:
Otowski, W.
Lewińska, G.
Powiązania:
https://bibliotekanauki.pl/articles/1198576.pdf
Data publikacji:
2014-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.Pq
61.30.Eb
64.70.M-
42.70.Df
Opis:
(4-(4'octylobiphenyl)carboxylan) 4-(2-methylobuthyl) phenol (CE8), the substance showing complex polymorphism, has been investigated using the dielectric spectroscopy method. This substance exhibited polymorphism during heating and cooling: a few smectic phases, a cholesteric phase, and a blue phase as well. Despite the fact that the substance polymorphism depends on the rate of heat flow existing of the blue phase has been confirmed by polarizing microscopic observations as well as dielectric spectroscopy investigations.
Źródło:
Acta Physica Polonica A; 2014, 125, 5; 1152-1158
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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