共查询到19条相似文献,搜索用时 125 毫秒
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钽酸锂晶体具有优异的压电性能,是声表面波(SAW)滤波器广泛使用的衬底材料。该文采用自主研制的提拉单晶炉,成功生长出4英寸、42°Y方向、外观完整的钽酸锂晶体。经可见及近红外分光光度计测试,晶体透过率接近80%;经X线摇摆测试,其半高全峰宽(FWHM)为28.4″,单晶性较好;采用差热分析仪对生长的晶体头尾进行居里温度测试,居里温度偏差为4.4 ℃。声表面波性能测试结果表明,钽酸锂晶体的声表面波速度、机电耦合系数和频率温度系数等指标均满足SAW滤波器的使用要求。 相似文献
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在利用晶体的电光效应实现快速变焦时,需要合理地设计电光晶体及电极结构。基于晶体电光效应的基本原理,提出了其设计的基本原则和思路,并通过对一次电光晶体(铌酸锂晶体)和二次电光晶体(钽铌酸钾晶体)内部非均匀电场及其总附加光程的模拟和比较,获得了优化的电光晶体及电极设计结果。在此基础上,开展了电光晶体用于快速变焦设计的性能分析,并讨论了电光晶体长度、外加电压等参数对总附加光程的影响。结果表明:电光晶体的附加光程调制的曲率半径随控制电压增大而减小,在加载电压不变的情况下随晶体厚度的增大而增大。因此,在实际应用中,需要对晶体厚度和加载电压综合进行考虑,以获得最佳的变焦效果。 相似文献
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该文使用具有低电容比、宽调谐范围的钽酸锂晶体设计了一巴特勒共基低相位噪声压控振荡器,此设计在寻求高有载品质因数QL的同时保持了振荡器的输出功率。使用的钽酸锂晶体的无载品质因数Q0约为1.24×103,其频率为10.727MHz。设计出的巴特勒振荡器QL≈33%Q0,输出功率约为11dBm。不加压控的情况下,实际测得该振荡器的相位噪声结果为-85dBc/Hz@10 Hz和-145dBc/Hz@1kHz。在此基础上,增加一变容二极管作为压控元件设计了钽酸锂压控振荡器,在2~10 V范围内,测得控制电压压控斜率约为86.6×10-6/V,相位噪声测试结果优于-82dBc/Hz@10Hz和-142dBc/Hz@1kHz,实现了具有宽调谐范围的低相位噪声钽酸锂振荡器的设计。 相似文献
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介绍了光学相控阵技术的发展背景和工作原理,研究了国内外基于不同电光材料(钽酸锂、PLZT、AlGaAs和液晶)光学相控阵技术的进展,探讨了光束扫描(指向)控制存在的扫描机械问题及光学相控阵具有的功能优势,针对光学相控阵器件的现状,提出了光学相控阵材料技术的研究方向及光学相控阵技术的应用前景。 相似文献
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I. V. Kubasov A. V. Popov A. S. Bykova A. A. Temirov A. M. Kislyuk R. N. Zhukov D. A. Kiselev M. V. Chichkov M. D. Malinkovich Yu. N. Parkhomenko 《Russian Microelectronics》2017,46(8):557-563
Bidomain single crystals of lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) are promising materials for use as actuators, mechanoelectrical transducers, and sensors capable of working in a wide temperature range. One need to take into account the anisotropy of the properties of the crystalline material when such devices are designed. In this study we investigated deformations of bidomain round shaped Y + 128°-cut wafers of lithium niobate in an external electric field. The dependences of the piezoelectric coefficients on the rotation angles were calculated for lithium niobate and lithium tantalate and plotted for the crystal cuts which are used for the formation of a bidomain ferroelectric structure. In the experiment, we utilized an external heating method and long-time annealing with the lithium out-diffusion method in order to create round bidomain lithium niobate wafers. Optical microscopy was used to obtain the dependences of the bidomain crystals’ movements on the rotation angle with central fastening and the application of an external electric field. We also modelled the shape of the deformed bidomain wafer with the suggestion that the edge movement depends on the radial distance to the fastening point quadratically. In conclusion, we revealed that the bidomain Y + 128°-cut lithium niobate wafer exhibits a saddle-like deformation when a DC electric field is applied. 相似文献
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The analysis of intermodulation in X-cut lithium tantalate resonators is performed and applied to the evaluation of the fourth-order nonlinear elastic coefficient. A comparison with an AT-cut quartz resonator indicates that lithium tantalate nonlinearities are much lower. 相似文献
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The effects of X- and gamma radiation on an optical waveguide, fabricated in lithium tantalate, are described and discussed. The measurements indicate that quite severe radiation environments would be necessary to produce significant problems with LiTaO/sub 3/ devices. However, the level of the radiation effects may depend, like those in semiconductor devices and fibre optics, on the details of the composition of the material and the constructional methods employed. Because there appear to be effects due to a radiation-induced, internal, electric field, there will be a dependence on the cut of the crystal used.<> 相似文献
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本文简要介绍钽酸锂晶体及器件的一些特性,对用该材料制作的21.4MHz宽带滤波器的设计、制作和测试结果作了较详细的介绍,滤波器的带宽达225kHz,矩形系数(BW_(?0dB)/BW_(3dB)为2.66,带外衰减在50dB以上。该材料在做宽带滤波器和压控振荡器方面具有优越性。 相似文献
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A guided-wave acoustic-optic Bragg cell has been fabricated for the first time, to our knowledge, on lithium tantalate. The waveguide is fabricated by dilute melt proton-exchange, and without electrical tuning a maximum diffraction efficiency of 22% has been demonstrated. In addition, the thermo-optic behaviour of the lithium tantalate waveguide has been shown to be similar to that previously demonstrated on titaniumindiffused and proton-exchange lithium niobate waveguides 相似文献
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3~5 m 中红外激光在光电对抗领域有着重要的应用前景。如果中红外激光进入皮秒量级,将使其具有更高的峰值功率和作战效能。文中采用1.06 m 皮秒激光器泵浦单周期极化化学计量比钽酸锂晶体(周期为29.5 m)光参量产生器的方案,来获得皮秒中红外激光输出。其中皮秒泵浦源为自制的侧面泵浦结构1.06 m 皮秒再生放大器。该激光器在1 kHz 重复频率下,输出功率最高为2.02W,脉冲宽度为13.6 ps。光参量发生器采用温度调谐方式,获得了3.98~3.68 m(晶体从40~200℃)皮秒中波红外可调谐激光输出。在最高泵浦功率泵浦,晶体温度为120℃时,获得最大中红外激光输出(闲频光)190 mW,光光转换效率达9.4%,充分验证了采用OPG 的方式获得瓦级皮秒中红外激光输出的可行性。 相似文献
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A method for modifying the surface free energy of lithium tantalate (LT) ferroelectric crystals is reported. Ultraviolet illumination
and low-energy electron irradiation have been used for tuning the surface free energy (wettability) resulting in a wide range
of contact angles (6 deg to 87 deg). The ultraviolet (UV) illumination makes the LT crystal surface superhydrophilic while
the low-energy electron irradiation decreases the surface wetting. Fabrication of various wetting configurations allows demonstration
of high-quality direct bonding of LT plates with hydrophilic polar faces. 相似文献