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Tytuł:
Breakdown of Rotational Symmetry at Semiconductor Interfaces: a Microscopic Description of Valence Subband Mixing
Autorzy:
Cortez, S.
Krebs, O.
Voisin, P.
Powiązania:
https://bibliotekanauki.pl/articles/2014160.pdf
Data publikacji:
2000-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Fm
78.20.Jq
Opis:
The recently discovered in-plane optical anisotropy of [001]-grown quantum wells offers a new theoretical and experimental insight into the electronic properties of semiconductor interfaces. We first discuss the coupling of X and Y valence bands due to the breakdown of rotation inversion symmetry at a semiconductor hetero-interface, with special attention to its dependence on effective parameters such as the valence band offset. The intracell localization of Bloch functions is explained from simple theoretical arguments and evaluated numerically from a pseudo-potential microscopic model. The role of envelope functions is then considered, and we discuss the specific case of non-common atom interfaces. Experimental results and applications to interface characterization are presented. These calculations give a microscopic justification, and establish the limits of the heuristic "H$\text{}_{BF}$" model.
Źródło:
Acta Physica Polonica A; 2000, 98, 3; 303-323
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Free Carrier Concentration on Nonlinear Absorption of n-Type ZnSe Crystals
Autorzy:
Sahraoui, B.
Chevalier, R.
Nguyen Phu, X.
Rivoire, G.
Bała, W.
Powiązania:
https://bibliotekanauki.pl/articles/1952689.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Jq
78.30.Hv
Opis:
The dependence of nonlinear absorption at 532 nm of n-type ZnSe crystals upon annealing temperature and free carrier concentration is reported. The nonlinear optical absorption as well as the efficiency of degenerate four wave mixing of ZnSe are investigated. It is found that the magnitude of the nonlinear absorption decreases with an increase in the electron concentration. The nonlinear refractive index change is estimated.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 1070-1074
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Allocation and Properties of Iron States in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Te in Forbidden Gap Energy Range
Autorzy:
Hołda, A.
Rodzik, A.
Melnikov, A.
Żukowski, P. W.
Powiązania:
https://bibliotekanauki.pl/articles/1872765.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ci
78.20.Jq
78.60.Hk
Opis:
The use of different experimental methods (reflectivity, absorption, photoconductivity and cathodoluminescence) allowed us to confirm the existence of the deep donor-like state of iron and present allocation and properties of the iron states in Cd$\text{}_{1-y}$Fe$\text{}_{x}$Te (0 ≤ x ≤ 0.05) at 300 K and 77 K in the forbidden gap energy range. It was concluded that the increase in width of the forbidden gap with the change of temperature from 300 K to 77 K leads mainly to the rise of the energy distance between the donor-like iron state $\text{}^{5}$E and the bottom of the conduction band.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 357-360
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Properties of Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se Epilayers Studied by Spectroscopy Methods
Autorzy:
Głowacki, G.
Gapiński, A.
Derkowska, B.
Bała, W.
Sahraoui, B.
Powiązania:
https://bibliotekanauki.pl/articles/1969076.pdf
Data publikacji:
1998-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
78.20.Jq
78.66.Hf
Opis:
Linear optical properties of the Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se (0 ≤ x ≤ 0.4) alloys have been studied using reflectance, spectroscopic ellipsometry and photoluminescence measurements. The refractive indices of Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se epilayers were investigated as a function of Mg composition (0 ≤ x ≤ 0.4). The energies of band gap E$\text{}_{g}$ and spin-orbit splitting E$\text{}_{g}$+Δ, have been determined. These energies are shifted gradually to higher values with increasing Mg content.
Źródło:
Acta Physica Polonica A; 1998, 94, 2; 321-325
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electro-Optical Properties of Liquid Crystals Composite with Zinc Oxide Nanoparticles
Autorzy:
Eskalen, H.
Özğan, Ş.
Alver, Ü.
Kerlı, S.
Powiązania:
https://bibliotekanauki.pl/articles/1398924.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Jq
77.84.Nh
78.20.Fm
Opis:
In this study, zinc oxide (ZnO) nanoparticles were synthesized by spray pyrolysis method. The properties of ZnO nanoparticles are determined by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and UV-vis spectroscopy. Nematic liquid crystal mixture E7 was doped with 1, 2, and 4% ZnO. We investigate electrical and optical parameters of pure and doped nematic liquid crystal mixture E7. The experiments related to voltage dependence and light transmittance of the pure and doped E7 were carried out. The values of threshold voltage, total phase retardation and birefringence are examined. The results show that doping zinc oxide nanoparticles into liquid crystal mixture E7 decreases threshold voltage significantly.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 756-760
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Symmetry and Optical Phenomena
Autorzy:
Malinowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1887426.pdf
Data publikacji:
1991-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
78.20.Bh
78.20.Jq
Opis:
The explicit forms of the broken (by a electric field E, magnetic field H and spatial dispersion of wave vector k) point symmetry groups of a crystal are given. For these groups the dielectric permeability tensors: ε$\text{}_{ij}$(ω, E), ε$\text{}_{ij}$(ω, H) and ε$\text{}_{ij}$(ω, k) - the particular cases of ε$\text{}_{ij}$(ω, E, H, k) - are written out (the susceptibility tensors χ$\text{}_{ij}$(ω, E), χ$\text{}_{ij}$(ω, H) and χ$\text{}_{ij}$(ω, k) take the same forms). In order to illustrate the results obtained the electrooptical phenomena (connected with the tensors ε$\text{}_{ij}$(ω, E)) are discussed.
Źródło:
Acta Physica Polonica A; 1991, 79, 4; 565-589
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Highly Compensated GaAs Crystal Obtained by Molecular CO Doping
Autorzy:
Bożek, R.
Korona, K. P.
Nowak, G.
Wasik, D.
Słupiński, T.
Kaczor, P.
Powiązania:
https://bibliotekanauki.pl/articles/1929707.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
78.55.-m
78.20.Jq
Opis:
GaAs:C crystal was grown by liquid encapsulated Czochralski technique with large partial pressure of CO in ambient atmosphere p$\text{}_{CO}$/p$\text{}_{tot}$ = 0.2 and investigated using near and infrared absorption, photoluminescence, photoconductivity, photo-induced current transient spectroscopy and photo-Hall measurements. High resistivity of the crystal was found in electrical measurements (10$\text{}^{7}$ Ω cm, the Fermi level at 0.67 eV below conduction band at 300 K). Local vibrational mode revealed increased concentration of carbon acceptor and presence of oxygen related complexes. Photoluminescence spectra were dominated by two bands with peak energies at 1.49 eV and 0.8 eV. The near band gap emission shifts with excitation intensity up to 4 meV/decade. In photocurrent spectrum a strong photoionization band with E = 0.55 eV is observed.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 669-672
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Optical Method of Determining the Point Symmetries
Autorzy:
Malinowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1887979.pdf
Data publikacji:
1991-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.16.-d
78.20.Bh
78.20.Jq
78.20.Ls
Opis:
The present symmetry theory of optical phenomena makes it possible to determine each of 122 point symmetry groups both for non-dispersive as well as dispersive media. This is achieved by considering the symmetry breaking effect external fields (separately E and H) on the propagation of electromagnetic waves. The corresponding results are collected in Tables I-III. The way of measuring the relevant physical quantities is proposed. The point symmetry of a given sample is obtained by comparing the experimental results with their theoretical counterparts. The results given in Tables I-III can also be viewed as the discussion of the "canonical" solutions (effects) for a given symmetry K.
Źródło:
Acta Physica Polonica A; 1991, 80, 1; 61-79
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogen-Like Excitations of 3d and 4f Isoelectronic Impurities in Semiconductors
Autorzy:
Sokolov, V. I.
Powiązania:
https://bibliotekanauki.pl/articles/1945561.pdf
Data publikacji:
1996-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.+z
78.20.Jq
78.20.Wc
78.50.Ge
Opis:
In the paper the energy states of structured isoelectronic impurities of transition metals and rare earth elements, donor and acceptor excitons of 3d and 4f impurities, the role of donor and acceptor excitons of 3d and 4f impurities in energy transfer from the matrix to impurities are discussed. It is shown that structured impurities may be classified as "open" and "closed" isoelectronic impurities. The number of electrons in the 3d or 4f shells is changed at hω < E$\text{}_{g}$ not changed structure levels generated by forbidden gap properties donor acceptor excitons those energy transfer mechanisms from matrix to an impurity (a capture carriers into 3d or 4f shells open and auger process essentially distinguished two kinds structured isoelectronic for closed impurities a model is discussed in frame which the spectra of electroabsorption photoluminescence cathodoluminescence are described.
Źródło:
Acta Physica Polonica A; 1996, 90, 2; 245-256
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric and Electrooptic Investigations of B Phases οf Banana-Shaped Thioesters
Autorzy:
Wierzejska-Adamowicz, M.
Ossowska-Chruściel, D.
Chruściel, J.
Douali, R.
Legrand, Ch.
Marzec, M.
Mikułko, A.
Sikorska, A.
Wróbel, S.
Powiązania:
https://bibliotekanauki.pl/articles/1538244.pdf
Data publikacji:
2010-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.84.Nh
77.84.-s
78.20.Jq
Opis:
Electrooptic and dielectric measurements were done for B phases of two banana-shaped homologues 1,3-phenylene bis{4-[(4-nonylo-xy-benzoyl)sulfanyl]benzoate (9OSOR) and 1,3-phenylene bis{4-[(4-dodecylo-xy-benzoyl)sulfanyl]benzoate (12OSOR). Polarizing microscopy allowed to identify $B_{1}$ phase for 9OSOR and $B_{2}$ phase for 12OSOR on the basis of texture observation. Spontaneous polarization measurements were performed using reversal current method. The current response to applied triangular voltage shows that $B_{1}$ phase is a ferroelectric and $B_{2}$ phase - antiferroelectric one for which two well separated peaks were observed. Polarization for phase $B_{1}$ of 9OSOR is rather small and its temperature dependence is unusual for ferroelectric liquid crystals - it increases with temperature. Spontaneous polarization for $B_{2}$ phase of 12OSOR compound is of about 600 nC/$cm^{2}$. Dielectric spectra measured with bias field for $B_{2}$ phase of 12OSOR show two well separated relaxation processes. In the low frequency range the relaxation process is connected with fluctuations of ferroelectric domains. The relaxation process in the high frequency range appearing also without bias field is connected with molecular reorientation. The dielectric spectra measured for $B_{1}$ phase of 9OSOR with and without bias voltage showed only one dielectric relaxation process connected with molecular reorientation around the short axis.
Źródło:
Acta Physica Polonica A; 2010, 117, 4; 557-561
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Real Time Imaging of Propagating High Field Domains in Semi-Insulating GaAs
Autorzy:
Piazza, F.
Christianen, P. C. M.
Maan, J. C.
Powiązania:
https://bibliotekanauki.pl/articles/1933946.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Jq
78.47.+p
07.60.-j
72.20.Ht
Opis:
With a newly developed technique, we measure voltage, electric field and charge distribution of high field domains in semi-insulating GaAs under high electric bias. Based on these new quantitative data resolved in time and space, which are synchronized with the current pulses, we confront the generally accepted model which explains the domain formation with field enhanced trapping from EL2.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 865-868
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of Linear Electro-Optic Coefficients in La₃Ga₅SiO₁₄ Crystals
Autorzy:
Ftomyn, N.
Shopa, Ya.
Sudak, I.
Powiązania:
https://bibliotekanauki.pl/articles/1030853.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Jq
32.10.Dk
78.20.Ek
61.50.Ah
Opis:
The values of electronic polarizabilities of La³⁺, Ga³⁺, Si⁴⁺, O²¯ ions are specified using new experimental data about optical activity of La₃Ga₅SiO₁₄ crystals. A calculation technique based on the dipole electron shifting model is applied to estimate linear electrooptic coefficients for the La₃Ga₅SiO₁₄. Wavelength dependences of the both linear electro-optic tensor components r₁₁ and r₄₁ are calculated.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 933-935
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electro-Optical Properties of II-VI Superlattices
Autorzy:
Schillak, P.
Czajkowski, G.
Powiązania:
https://bibliotekanauki.pl/articles/2047684.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Cc
73.21.Cd
74.25.Gz
78.20.Jq
78.67.-n
Opis:
We show how to compute electro-optical spectra of semiconductor superlattices in the region of interband electronic transitions. The method uses the microscopic calculation of eigenvalues and eigenfunctions and the macroscopic real density matrix approach to compute the electromagnetic fields and susceptibilities. The electron-hole screened Coulomb potential is adapted and the valence band structure is taken into account in the cylindrical approximation, thus separating light- and heavy-hole motions. We calculate the electro-optical functions, including the optical Stokes parameters and ellipsometric functions for the case of oblique incidence. Results are given for Zn$\text{}_{1-x}$Cd$\text{}_{x}$Se/ZnSe superlattices and a good agreement with experiments is obtained.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 301-304
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acousto-Optic Characteristics in Media with Strong Acoustic Anisotropy
Autorzy:
Voloshin, A.
Balakshy, V.
Powiązania:
https://bibliotekanauki.pl/articles/1383287.pdf
Data publikacji:
2015-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.hb
42.79.Jq
Opis:
Calculations of acousto-optic diffraction spectrum are fulfilled on the basis of modified Raman-Nath equations which take into consideration the acoustic energy walk-off. It is shown that, depending on acousto-optic interaction geometry, the walk-off can change essentially angular and frequency ranges of the interaction. Coefficients of broadening are put in practice as characteristics of the walk-off influence. The calculations are carried out for 5° crystal cut of a paratellurite crystal in wide ranges of ultrasound frequencies and Bragg angles.
Źródło:
Acta Physica Polonica A; 2015, 127, 1; 60-62
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acousto-Optic Modulator Driven by Surface Acoustic Waves
Autorzy:
Kakio, S.
Powiązania:
https://bibliotekanauki.pl/articles/1377937.pdf
Data publikacji:
2015-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.79.Jq
43.35.Sx
78.20.Hp
78.20.hb
Opis:
In this paper, an introduction to the design, fabrication, evaluation, and application of acousto-optic modulators using the Bragg diffraction of an optical guided wave in a channel optical waveguide due to a surface acoustic wave is provided. First, the surface acoustic wave mode dependence in the acousto-optic Bragg diffraction was discussed by considering the surface acoustic wave power required for the maximum diffraction $P_100$ calculated using coupled mode theory and the measured $P_100$ in Ti-diffused planar optical waveguides fabricated on $LiNbO_3$ substrates. Next, performances of several devices that the author and the coworkers developed are reviewed. These include a waveguide-type acousto-optic modulator using a tapered crossed-channel proton-exchanged optical waveguide on a 128°-rotated Y-cut $LiNbO_3$ substrate for an optical wavelength of 1.55 μm, a monolithically integrated tandem acousto-optic modulator in which several waveguide-type acousto-optic modulators are connected in tandem on the same substrate, and a waveguide-type acousto-optic modulator in which laser lights of the three primary colors, red, green, and blue, can be modulated by the same modulator at the same driving frequency.
Źródło:
Acta Physica Polonica A; 2015, 127, 1; 15-19
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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