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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:
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:
Acousto-Optical Tunable Transmissive Grating Beam Splitter
Autorzy:
Dieulangard, A.
Kastelik, J.
Dupont, S.
Gazalet, J.
Powiązania:
https://bibliotekanauki.pl/articles/1383325.pdf
Data publikacji:
2015-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.hb
42.79.Jq
43.35.Sx
Opis:
We present a tunable transmissive grating beam splitter for multiple laser line separation based on acousto-optic interaction in tellurium dioxide. Acousto-optic devices are well known for light modulation, frequency shifting, filtration or deflection. Unlike the classical operating modes of acousto-optic devices, we consider the simultaneous diffraction of several optical wavelengths by a single ultrasonic frequency. The device is based on the Bragg anisotropic interaction in the specific "tangent phase matching" configuration. The acousto-optic interaction takes place with a single ultrasonic frequency and the diffraction efficiency remains high over a wide optical spectral range. The different diffracted beams are then angularly well separated, due to the slow velocity of the ultrasonic wave propagating in tellurium dioxide. The optical bandwidth is directly related to the operating ultrasonic frequency. Numerical calculations were carried out to determine the main parameters of the device: operating ultrasonic frequency, optical bandwidth, tunability range, crystalline cut and transducer length. A practical device has been designed for visible spectrum. Experimental results are presented as for example a spectral bandwidth from 450 nm to 550 nm with a carrier frequency $f_0$=125 MHz.
Źródło:
Acta Physica Polonica A; 2015, 127, 1; 66-68
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:
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:
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:
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:
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
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:
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:
New Method to Calculate Spatial Distribution of Acousto-Optic Figure of Merit in Crystals
Autorzy:
Muromets, A.
Trushin, A.
Powiązania:
https://bibliotekanauki.pl/articles/1383519.pdf
Data publikacji:
2015-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.hb
42.79.Jq
43.35.Cg
62.30.+d
46.15.-x
78.20.Bh
Opis:
We propose a novel method to calculate acousto-optic figure of merit in crystals. Calculations are performed in laboratory coordinate system where Z'-axis is collinear with wave vector of ultrasound and the Fresnel equation is considered as an equation on the third component of refractive index vector. The method is applicable to both uniaxial and biaxial crystals. In this paper, we compared obtained values of acousto-optic figure of merit with values from literature data for uniaxial crystals such as paratellurite, lithium niobate, tellurium and for biaxial crystals such as lead and strontium tetraborates. Calculations in paratellurite were carried out for slow-shear acoustic wave propagating along [110] crystal axis. In lithium niobate crystal, we perform comparison with results for geometry of acousto-optic interaction where acoustic wave vector forms 88° angle with X crystal axis and 150.4° angle with Z crystal axis. In tellurium crystal, we investigate geometries applied in infrared deflectors. In $SrB_4O_7$ and $PbB_4O_7$ crystals we analyze acousto-optic characteristics of slow-shear mode propagating along [100] crystal axis. Spatial distributions of acousto-optic figure of merit and acoustic frequency for the mentioned acousto-optic interaction geometries are presented.
Źródło:
Acta Physica Polonica A; 2015, 127, 1; 93-95
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:
Acoustic Modes Transformation upon Reflection in Tellurium Dioxide Crystal
Autorzy:
Polikarpova, N.
Voloshinov, V.
Powiązania:
https://bibliotekanauki.pl/articles/1383533.pdf
Data publikacji:
2015-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Hp
42.79.Jq
43.35.Sx
43.35.+d
Opis:
Generation of acoustic shear waves in crystals is one of the main problem of acousto-optics. Launching of the shear waves is much more difficult than the longitudinal modes because of difficulties related to acoustic contact and also because of problems arising from matching of acoustic and electric parameters of piezoelectric transducer. We obtained the transverse waves as a result of longitudinal-shear modes reflection in a crystal. Crystals having the required effect should possess a strong anisotropy of their elastic properties to realize the effective acoustic mode transformation. In this paper, one of the important cases of the acoustic waves reflection is investigated theoretically and experimentally. The research was carried out in the crystal of paratellurite.
Źródło:
Acta Physica Polonica A; 2015, 127, 1; 96-98
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:
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

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