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    Wyświetlanie 1-15 z 15
    Tytuł:
    Regular Trends of Acousto-Optic Interaction in Terahertz Region of Electromagnetic Radiation
    Autorzy:
    Nikitin, P.
    Voloshinov, V.
    Gerasimov, V.
    Knyazev, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1383228.pdf
    Data publikacji:
    2015-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.20.hb
    42.25.Fx
    Opis:
    Basic problems of acousto-optic interaction in terahertz region of electromagnetic spectrum are considered. We obtained experimental results that are fitted by generalized theoretical model developed with the goals to describe the interaction in detail. Our analysis showed that crystalline germanium is one of the best materials to observe the acousto-optic interaction in the terahertz range. The carried out study proved that a germanium based acousto-optic device could be used for fast and reliable deflection of monochromatic radiation in the terahertz spectral region.
    Źródło:
    Acta Physica Polonica A; 2015, 127, 1; 49-51
    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:
    Photoelastic Phenomena in Stressed Laser Heterostructures
    Autorzy:
    Kulakova, L.
    Averkiev, N.
    Lutetskiy, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1383501.pdf
    Data publikacji:
    2015-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.20.-e
    78.20.Bh
    78.20.hb
    Opis:
    The theoretical analysis of optical properties change in cubic crystals caused by simultaneous action of longitudinal and shear strains due to the photo-elastic interaction has been performed. The polarization characteristics change of a primary linear polarized light wave during propagation in the crystal has been studied. Results of the calculations were used to analyze photo-elastic phenomena in stressed heterostructures at the introduction of an alternating shear strain. The comparison of photo-elastic and acousto-electron phenomena in the laser heterostructures has been fulfilled. The results have been confirmed by the experiments in the InGaAs/GaAs structures at the action of shear strains excited by the ultrasonic waves.
    Źródło:
    Acta Physica Polonica A; 2015, 127, 1; 87-89
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Acousto-Optic Tunable Filters for Imaging Applications in the 2-4 μm with Low RF Drive Power
    Autorzy:
    Valle, S.
    Ward, J.
    Pannell, C.
    Johnson, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/1383267.pdf
    Data publikacji:
    2015-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    62.20.-x
    78.20.hb
    62.40.+i
    Opis:
    The $λ^{2}$ dependence on acoustic field intensity (and hence RF drive power) can render large aperture acousto-optic tunable filters impractical for many applications beyond about 2 μm. One potential technique for reducing the RF drive-power requirement is to configure an acousto-optic tunable filter such that the interaction region is at acoustic resonance. We describe an acousto-optic tunable filter that operates at resonance and present an analysis of the predicted performance. In addition, we address the practical issues in deploying such a scheme. Finally, we present results of a prototype "resonant acousto-optic tunable filter" operating in the 1-2 μm region.
    Źródło:
    Acta Physica Polonica A; 2015, 127, 1; 58-59
    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:
    Acousto-Optic Diffraction by Shear Horizontal Surface Acoustic Waves in 36° Rotated Y-Cut X-Propagation Lithium Tantalate
    Autorzy:
    Rimeika, R.
    Čiplys, D.
    Shur, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1383242.pdf
    Data publikacji:
    2015-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    77.65.Dq
    43.35.Sx
    78.20.hb
    Opis:
    We have investigated the acousto-optic diffraction by shear horizontal surface acoustic waves in 36° rotated Y-cut X-propagation lithium tantalate ($LiTaO_3$) crystals. The measurements were performed at the optical wavelength 633 nm of He-Ne laser and acoustic wavelengths of 50-60 μ m. The anisotropic diffraction with the light polarization rotation in the transmission mode was observed. The measured and calculated values of the light incidence angle corresponding to the strongest diffraction differed significantly. A narrow strip of a thin metal film deposited on the crystal surface drastically affected the light diffraction. We attribute these effects to the conversion processes between the shear horizontal leaky surface acoustic wave and shear horizontal surface skimming bulk wave.
    Źródło:
    Acta Physica Polonica A; 2015, 127, 1; 52-54
    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:
    Sensing Sound Pressure in an Anechoic Chamber Using Backscattered Laser Light
    Autorzy:
    Piper, B.
    Koukoulas, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1383751.pdf
    Data publikacji:
    2015-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    06.20.-f
    42.62.Eh
    43.58.+z
    78.20.hb
    Opis:
    Current standards for the measurement of the SI derived unit of sound-in-air pressure, the pascal, are based upon microphone reciprocity calibration and are achieved indirectly through microphone sensitivity. These methods require microphones of specific geometry and performance characteristics, effectively artefacts, and are traceable through standards for electrical and dimensional units. Measurement of acousto-optic interactions can provide a direct approach to measuring sound pressure. One acousto-optic interaction is the periodic scattering of photons caused by particles moving in a sinusoidal manner due to propagating sound across interference fringes formed at the intersection of two coherent laser beams. The sequence of these scattered photons, which is collected using telescopic optics and generated by a single photon counting device, can be autocorrelated to yield the periodicity of the photon events. Through mathematical analysis of the autocorrelation function it has been shown that acoustic particle velocity is inversely proportional to the time of the first minimum. This has effectively been shown for measurements in acoustic standing wave tubes and has been developed into a method which can be applied in an anechoic chamber. This paper describes the design and implementation of such a system which allows for a comparison of sound pressure measurements using optical and microphone based techniques.
    Źródło:
    Acta Physica Polonica A; 2015, 127, 1; 128-131
    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:
    Weak Ferromagnetism of Fe Intercalated Fullerides
    Autorzy:
    Byszewski, P.
    Diduszko, R.
    Baran, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1929859.pdf
    Data publikacji:
    1994-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.20.Ls
    76.70.Hb
    78.55.Kz
    Opis:
    The magnetic properties of C$\text{}_{60}$Fe$\text{}_{x}$ resemble spin glass with the freezing onset above 200 K. The unusual magnetization behavior at intermediate temperatures is ascribed to bonds reorganization.
    Źródło:
    Acta Physica Polonica A; 1994, 85, 2; 297-302
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    High-Pressure Studies of Semiconductors in the Far-Infrared: Donor States in Quasi-2D
    Autorzy:
    Weinstein, B. A.
    Tischler, J. G.
    Chen, R. J.
    Nickel, H. A.
    McCombe, B. D.
    Dzyubenko, A. B.
    Sivachenko, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2014129.pdf
    Data publikacji:
    2000-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.66.Fd
    73.20.Dx
    73.20.Hb
    Opis:
    We review recent experimental advances by the Buffalo group in performing far-infrared magnetospectroscopy under fine tuning of applied high hydrostatic pressure. Experiments are reported for the effects of pressure on Si donors in modulation doped GaAs/AlGaAs quantum wells. We clearly observe pressure-mediated competition between free (i.e., Landau level) and bound electron states - the latter arising from both neutral (D$\text{}^{0}$) and charged (D$\text{}^{-}$) donor species. With increasing pressure, there is a progression of the observed spectra from being dominated by cyclotron resonance and the D$\text{}^{-}$ singlet (or singlet-like bound magnetoplasmon) transitions, to showing the D$\text{}^{0}$ 1s → 2p$\text{}^{+}$ line. The main reason for this evolution is the decrease in electrons due to the crossover of the Si levels associated with the Γ (well) and X (barrier) conduction minima. Indeed, for pressures above 30 kbar the Γ(well)-X(barrier) crossover quenches all the transitions. However, we find strong evidence that electrons are independently lost to a trap, which becomes active several kbar below this crossing. A possible candidate for this trap is residual Se impurities in the barriers. We present the results of detailed numerical calculation which are found to agree very well with the measured field dependencies of the cyclotron resonance, D$\text{}^{0}$ and D$\text{}^{-}$ transition energies. In the sample with the highest doping, a new transition is observed for fields and pressures above 7.5 T and 5 kbar. Reasons for this apparent anomaly are discussed.
    Źródło:
    Acta Physica Polonica A; 2000, 98, 3; 241-257
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spectroscopy of Charged Donors and Many-Electron Effects in Semiconductor Quantum Wells
    Autorzy:
    McCombe, B. D.
    Jiang, Z. X.
    Tischler, J. G.
    Weinstein, B. A.
    Hawrylak, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/2011126.pdf
    Data publikacji:
    1999-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.20.Dx
    73.20.Hb
    78.66.Fd
    Opis:
    Far infrared magnetospectroscopic studies of negative donor ions (D$\text{}^{-}$), and donors in the presence of many excess electrons in high magnetic fields in GaAs/AlGaAs quantum wells are reviewed. Both singlet and triplet transitions of well-center D$\text{}^{-}$ions were observed and are in good agreement with recent theoretical calculations. For off-well-center D$\text{}^{-}$ions evidence for a predicted magnetic-field-induced "unbinding" of the second electron was found. In the presence of many excess electrons the D$\text{}^{-}$singlet and -triplet transitions are blue-shifted substantially and evolve into bound magnetoplasmon excitations. Cusps are observed at integral and fractional Landau-level filling factors (ν) in a plot of normalized blue-shift of the D$\text{}^{-}$singlet-like bound magnetoplasmon transition vs. ν. For ν<1, the singlet-like bound magnetoplasmon transition continuously approaches the isolated D$\text{}^{-}$singlet transition with increasing magnetic field, while the triplet-like transition loses strength, irrespective of the electron density. Exact diagonalization studies of a donor ion with a few electrons in a parabolic lateral confining potential show the importance of electron-electron interactions and localization due to the long-range fluctuating potential in explaining this behavior. High pressure studies in a specially designed diamond anvil cell exhibit a continuous evolution from bound magnetoplasmon transitions to isolated D$\text{}^{-}$transitions to neutral donor transitions in a single sample as the pressure is increased and the electron density in the wells is decreased.
    Źródło:
    Acta Physica Polonica A; 1999, 96, 5; 559-572
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    AlGaAs to GaAs Energy Transfer Mechanisms in AlGaAs/GaAs Structures
    Autorzy:
    Karpińska, K.
    Godlewski, M.
    Żytkiewicz, Z. R.
    Chen, W. M.
    Weber, E. R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1921617.pdf
    Data publikacji:
    1992-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.20.Jv
    76.70.Hb
    78.55.Cr
    Opis:
    The results of photoluminescence and optically detected cyclotron resonance experiments are presented for thick AlGaAs epilayers grown by liquid phase electroepitaxy method on GaAs:Cr substrate. These results indicate an efficient energy transfer from excited AlGaAs to GaAs.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 4; 713-716
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mechanism of Optical Detection of Magnetic Resonance in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te
    Autorzy:
    Godlewski, M.
    Surma, M.
    Gałązka, R. R.
    Nguyen, The Khoi
    Gisbergen, S.J.C.H.M.
    Gregorkiewicz, T.
    Ammerlaan, C. A. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1921620.pdf
    Data publikacji:
    1992-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    76.70.Hb
    75.50.Pp
    78.20.Ls
    Opis:
    The photoluminescence and optically detected magnetic resonance studies of Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te (x = 0.095) are presented. The Mn$\text{}^{2+}$ magnetic resonance is detected optically via the changes of "edge" emission induced by the decrease of the Mn spin system magnetization.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 4; 717-719
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optically Detected Magnetic Resonance Studies of Te-Related Shallow Donors in Al$\text{}_{x}$Ga$\text{}_{1-x}$As
    Autorzy:
    Godlewski, M.
    Fronc, K.
    Chen, W. M.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1890838.pdf
    Data publikacji:
    1991-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Eq
    72.20.Jv
    76.70.Hb
    78.55.Cr
    Opis:
    The first studies of the Optically Detected Magnetic Resonance (ODMR) of Te-doped (x = 0.42) are presented. The ODMR data indicate an efficient energy transfer between epilayer and GaAs substrate.
    Źródło:
    Acta Physica Polonica A; 1991, 80, 3; 341-344
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-15 z 15

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