共查询到20条相似文献,搜索用时 15 毫秒
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给出了一种新的超声跟踪铌酸锂反常声光器件的优化设计方法,利用该方法系统计算了在不同入射角以及不同换能器片数情况下器件设计参数的准确数值。计算结果表明,该设计方法可以实现反常声光器件的超声跟踪,并且能够使器件获得更大的3 dB带宽和更高的衍射效率。 相似文献
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V. M. Kotov G. N. Shkerdin V. N. Ulasyuk 《Journal of Communications Technology and Electronics》2011,56(11):1350-1356
Two variants of acousto-optic interaction of multicolor radiation with one acoustic wave propagating in a paratellurite crystal
both at an angle to the optical axis of the crystal and orthogonally to the axis are analyzed. It is shown that, in the band
of wavelengths 0.475–0.525 μm, both variants have practically identical characteristics. However, the preference is given
to the second variant, because it is devoid of the drift of the acoustic wave, which makes it possible to produce acousto-optic
cells with smaller dimensions. 相似文献
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S. N. Antonov A. V. Vainer V. V. Proklov I. F. Yangirov 《Journal of Communications Technology and Electronics》2011,56(7):900-905
The features of the anisotropic acousto-optic Bragg diffraction in paratellurite related to the measurement and control of
the angular spectrum of monochromatic optical radiation are analyzed. We consider the diffraction configuration in which a
narrow angular component whose position is determined by the frequency of acoustic wave is deflected from the divergent optical
beam. The angular spectrum of optical radiation can be measured using variations in the acoustic frequency. It is demonstrated
that such a configuration can be used for the measurement of the angular spectrum of light and for the formation of the desired
angular distribution. 相似文献
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A. V. Vainer V. V. Proklov Yu. G. Rezvov O. D. Sivkova 《Journal of Communications Technology and Electronics》2017,62(10):1152-1164
The theory of acoustooptical (AO) interaction between light beams in the longitudinally inhomogeneous acoustic field is constructed with allowance for conditions typical of AO filtration. In the case of smooth acoustic inhomogeneities, analytical expressions for the spatially spectral characteristic relating the spatial spectra of incident and diffracted light beams are derived. The situation where a Gaussian light beam undergoes filtration in the acoustic field excited by a rectangular transducer is discussed in detail. The narrowband quasi-collinear AO filter based on a paratellurite crystal is simulated. It is demonstrated that the maximum diffraction efficiency and transmission-function shape distortion (with respect to the plane-wave model) of the given device depend to the greatest extent on the misalignment between the directions of the group velocities of interacting light beams. 相似文献
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I. E. Kuznetsova V. G. Mozhaev I. A. Nedospasov 《Journal of Communications Technology and Electronics》2016,61(11):1305-1313
The problem of the existence of pure shear backward waves and waves with zero group velocity is investigated for X-cut and Y-cut plates of orthorhombic crystal of potassium niobate, which distinguishes from the other crystals by exceptionally strong piezoelectric effect. The secular equations of the problem are derived in an explicit analytical form and they are studied numerically in the case of crystal-vacuum interface. Two factors contributing to the appearance of backward waves are identified: the negative displacement of the rays of bulk shear waves at oblique reflection from the surface in piezoelectric crystals and the concavity in cross section of the slowness surface for bulk shear waves near the X axis of the potassium niobate plate. The wide frequency ranges of the existence of symmetric and antisymmetric backward waves of the first and second orders are numerically found in the X-cut plate, for which both of these factors affect. To study the dispersion spreading of backward shear wave pulses, it is suggested to apply the parabolic equation corresponding to the second approximation in the dispersion theory. It is demonstrated that the “diffusion” coefficient in this equation vanishes at certain frequencies, leading to significant suppression of the dispersion distortions in the pulses of the waves under study. 相似文献
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两通道声表面波全光纤声光调制器的研究 总被引:3,自引:2,他引:1
研制了一种新型的两通道声表面波(SAW)全光纤声光调制器,建立了多通道声波与光纤中光导波相互作用的耦合模方程并求出其解。SAW全光纤声光器件由两通道SAW器件和单模光纤构成。光纤嵌入SAW器件,光纤中的光导波被声表面波调制,由于两个通道中的SAW具有不同的中心频率,所以光纤中的光导波可以被具有不同频率的两个通道的SAW同时调制。测试了器件,实现了全光纤相干调制解调。 相似文献
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The use of acousto-optic devices in real-time signal convolution and correlation has increased dramatically during the past decade because of improvements in device characteristics and implementation techniques. Depending on the application, processing can be implemented via spatial or temporal integration. Two-dimensional signal processing (including image processing) is possile, in spite of the inherent one-dimensional nature of the acousto-optic device as a spatial light modulator. 相似文献
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A new type of fiber acousto-optic device, based on tapered single-mode fiber, is described. Unlike earlier designs, the overlap between the acoustic and optical waves is complete, so very little acoustic power is required. Maximum coupling in an experimental device was attained for an electrical drive power of just 0.5 mW 相似文献
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Chunhui Zhu Zhuangzhi Li Heping An Guide Tang Denglu Hou 《Journal of Electronic Materials》2014,43(9):3666-3671
High-quality Ca3Co4O9 (CCO) thin films have been epitaxially grown on c-cut Al2O3 single crystal substrates using pulsed laser deposition (PLD). Different doses of Nb ions were injected into the films using an ion beam injection technique, and a nanoscale NbN x second phase was generated in the films after annealing in pure N2. The resistivity and Seebeck coefficient of the films were measured in the temperature range 175–375 K. The results demonstrated that the power factor of the films increases when injected with appropriate quantities of Nb. When the injected Nb concentration was 1.46 × 1020/cm3, the power factor of the film reached 0.17 mW/m K2 at room temperature, which is nearly twice as large as that for pure CCO film. A maximum value of 0.22 mW/m K2 was obtained at 375 K. 相似文献
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《Solid-State Circuits, IEEE Journal of》1977,12(1):10-13
An integrated optical (IO) hybrid circuit consisting of a photodetector array, waveguide, and acousto-optic modulator on a common silicon substrate has been fabricated. This IO hybrid circuit is a major step in the development of a combination optical-electronic processing system. In this device an array of p-n junction photodiodes was fabricated on a 2-in silicon wafer and a 7059 glass waveguide film sputtered over an SiO/SUB 2/ insulating layer on the wafer. Another SiO/SUB 2/ layer was deposited under the transducer electrode. The transducer was a 40-MHz lithium niobate rotated Y-cut crystal. A prism was used to couple in the light beam from a 5 mW He-Ne laser. The guided light beam was directed at one of the diodes in the array and pulsed RF signals were applied to the transducer. Oscillator frequencies of 40 MHz and 120 MHz were separately applied. Modulation depths of greater than 25 percent were produced. The fabrication of the optical guide photodiode and electrical interconnections on a single silicon wafer utilized standard IC fabrication techniques. 相似文献
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D. V. Bogomolov M. G. Mil’kov V. N. Parygin 《Journal of Communications Technology and Electronics》2006,51(1):94-100
A possibility of controlling the instrument function of acousto-optic devices with a noncollinear interaction geometry by using split piezotransducers is shown. A device’s instrument function can be corrected by modifying the distribution of the ultrasonic amplitude in an acousto-optic cell along the direction of propagation of optic beams. Optimum distributions of acoustic-deformation amplitudes are found, thus enabling reduction of the sidelobes of the device’s instrument function. The level of sidelobes is shown to depend both on the distribution of voltage amplitudes over sections of an acoustic transducer and on the width of the gap between these sections. An acousto-optic cell is developed and tested experimentally. It contains a piezotransducer consisting of eight sections that are power-supplied through a capacitance divider. 相似文献
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The design and fabrication of wide-band bulk acousto-optic modulators (temporal modulation) and beam deflectors (spatial modulation) are described. Optimized device parameters can be obtained systematically for given specifications of the desired modulation bandwidth, throughput efficiency and number of resolvable elements. As the device operating frequency goes beyond a few hundred megahertz, the acoustic transducer response becomes sensitive to the intermediate metal layers between the piezoelectric transducer and the acoustooptic interaction medium. Transducer bandwidth and impedance matching can be optimized using computer modeling programs. Criteria for material selection based on performance requirements and propagation loss are presented. Practical considerations for the fabrication of high performance devices and specific device parameters are discussed. 相似文献
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Thin film of lead dioxide, α-PbO2, has been grown by thermal evaporation technique on the single crystal of p-Si substrate and heterojunction photodiode, Au/α-PbO2/p-Si/Al, was fabricated. The current-voltage characteristics of the diode have been studied in the temperature ranged from 303 to 373 K and the voltage applied during measurements varied from −1 to 1.5 V. It was found from the (I-V) characteristics of the diode that the conduction mechanisms in the forward bias direction are controlled by the thermionic emission at bias potential ≤0.7 V followed by single trap space charge limited current (SCLC) conduction in the voltage range >0.7 V. The capacitance-voltage characteristics of the device were studied at room temperature in dark condition and it has been shown that the diode is abrupt junction. The carrier concentration on both sides of the depletion layer has been determined. Energy band diagram for α-PbO2/p-Si device was constructed. The device under illumination with light of intensity 20 W/m2 gives acceptable values of photoresponse parameters such as photosensitivity and photoconductivity. The presented photodiode parameters exhibit the typical photosensor applications with reproducibility phenomenon. 相似文献