光折变光子晶格中空间二次谐波的产生

用干涉法在自散焦光折变晶体 LiNbO₃：Fe中写入光子晶格的动态过程中，发现了双光束干涉条纹一分为二，四光束干涉点阵一分为四的分裂现象. 研究证明：这是干涉条纹空间频率的倍频现象，是入射的干涉光场与写入的光子晶格之间相互作用的结果. 本实验说明利用光折变效应可以容易地实现干涉光场空间频率的倍频和空间高次谐波的产生，并可利用产生的空间谐波感应出二倍频和高倍频的光折变光子晶格. 关键词： 光折变晶体 光子晶格 空间谐波     

基于主元分析的干涉仪相移器校准方法

利用主元分析从一组干涉图中提取相位和相移量,得到相移量与驱动电压之间的对应关系,从而实现压电陶瓷相移器的非线性校准.模拟结果表明:主元分析法计算相移量的误差随着干涉图中条纹根数的增多而减小;当干涉图中条纹根数多于0.25时,相移量计算误差小于0.1664rad.实验结果表明:相移量计算误差是周期分布,对相移器校准准确度影响小.该方法无需迭代计算,且对干涉图中条纹根数没有严格要求,因此是一种高效且实用的校准方法.     

光纤投影双频自动轮廓测量术

提出一种双频光纤投影自动轮廓测量技术；用一分二单模光纤耦合器产生正弦光强分布的投影光栅场；将光纤一臂绕在压电陶瓷（ＰＺＴ）环上述旁瓣通过压电陶瓷环引入相移值；以改变出射端两光纤间的距离来发迹投影光栅场的空间频率，用双频光栅技术实现复杂表面自动轮廓测量。     

频移阴影莫尔法

提出了一种新的莫尔条纹解调技术即频移法，它改变了莫尔条纹分布的频率，而相移莫尔法只是改变了莫尔条纹的相位。从阴影莫尔图分布的基本公式出发，借助于相移阴影莫尔法的思想推导并得出了频移阴影莫尔法的公式，在此基础上给出了特定条件下的产和公式。     

远场目标指示器

本专利的目标指示系统是采用相干光双光束照射分系统制成的。一束光改变一个频率级,使之区别于另一束光。光束从光源发散,直到叠射于要打击的目标上。光束重叠时的频差产生活动条纹干涉图,而活动条纹则对目标进行扫描。用各种不同的接收系统识别扫描的条纹并标明目标。此外,没有接收分系统,照射分系统也可用作测距装置。该装置经过调整,把光束调到能见到最大强度的活动条纹图,就可给出目标距离。     

低压微位移驱动电路及控制方法

讨论了低压微位移驱动电路及控制方法在光电轮廓仪上的运用。采用低压驱动电路驱动压电陶瓷相移器对参考光束进行相移，从而使仪器质量减轻、体积缩小、成本降低。在运用该电路时，为了解决压电陶瓷低电压区非线性误差大的问题，用PC计算机控制压电陶瓷上所加电压的电压值，由摄像头摄取图像并计算出干涉条纹的间隔，然后由PC计算机修改压电陶瓷上所加的电压值，直至干涉条纹相位差达到要求值。该方法的优点是：可消除压电陶瓷低压区的非线性误差，使得开环电路得到闭环的效果；可降低机械零部件的装配难度。     

信息光学视角下菲涅耳双棱镜干涉的研究

菲涅耳双棱镜干涉在相衬成像和全息显微术中有重要应用。为了促进其应用,本文从信息光学角度研究双棱镜干涉,首先利用光场与脉冲响应函数之间的关系,理论导出了菲涅耳双棱镜干涉条纹强度公式,分析并讨论了狭缝缝宽及狭缝到双棱镜距离对菲涅耳双棱镜干涉条纹的影响,狭缝宽度大于0. 1 mm时,干涉条纹分辨率变差。接着给出了改变狭缝宽度(变化量为0. 08 mm)和改变狭缝到双棱镜的距离(从8 cm变化到12 cm)的实验结果,理论分析和实验结果一致。该结果有助于促进菲涅耳双棱镜干涉在相衬成像等领域的应用。     

多普勒频移和干涉谱联合的水声目标运动参数估计

常见水中运动目标会辐射连续谱噪声和线谱噪声,连续谱噪声在浅海波导环境中形成明暗相间的干涉条纹。根据干涉条纹可以得到目标最近距离与速度的比值,无法直接解出两个参数值。针对利用干涉条纹无法分别估计最近距离与速度问题,提出一种多普勒频移、干涉条纹结合的运动参数估计方法。根据单条线谱多普勒频移得到最近距离与速度参数耦合曲线,再将该曲线与干涉条纹得到参数比值线相交,交点即为两参数估计结果。数值仿真估计声源运动速度、最近距离,在信噪比6 dB条件下,平均估计误差分别为0.71%与0.87%。将该方法应用在2021年6月大公岛海域海试数据,5组实验数据估计目标运动速度、最近距离平均误差分别为2.5%,4.4%,证明了方法的有效性。     

压电晶体位移特性曲线干涉自动测量方法

本文提出了压电晶体(PZT)位移物曲线自动干涉测量方法,该方法利用干涉仪把PZT的微位移量转化成干涉条纹相位变化量,通过快速傅里叶变换(FFT)方法自动复原干涉条纹中包含的相位的变化量,从而高精度地检测出PZT的位移特性曲线.根据该方法,利用CCD摄象机、图象板和干涉仪组合成一套光、机、电一体化的微位移自动测试系统,实际测量了我们研制的PZT随电压变化的位移特性曲线.实验表明,该方法原理实现简单,且能实现高精度、自动、实时和动态测量.     

毛细管干涉仪的理论分析

从几何光学出发,推导了毛细管干涉仪的从柱面透镜到接收屏的光线的光程．对光线追迹模拟,结果表明毛细管干涉仪的干涉条纹的形成可用双光束的干涉来解释．从柱面不同位置入射的两条光线可能具有相同的光程,而且从柱面透镜不同位置出发的两条光线可能到达接收屏的同一点,当它们满足相干条件时,就会形成干涉条纹．建立了干涉条纹的计算机模拟程序, 模拟了毛细管中液体折射率、毛细管内径、外径对干涉条纹的影响. 结果表明实验中应使用薄壁毛细管, 由于干涉条纹对柱面透镜到毛细管之间的距离非常敏感, 为提高精度, 建议在实验中用已知折射率的标样来确定这一距离.     

采用PZT动态调制的光纤光栅应变力测量技术

提出了一种新型PZT的动态调制光纤光栅应变力测量技术。把光谱仪对峰值波长移动的测量改变为示波器对峰值光功率时间间隔的测量 ,并对这种技术进行了理论分析和实验研究。用交变电压调制固定在光纤光栅上的PZT ,同时对施加在光栅上的应力进行测量。实践证明 ,测光脉冲时间间隔法与光谱峰值移动法的测量结果相同 ,而且两者与理论计算结果相符     

环形激光器反射镜相位延迟差测量方法研究

理论上推导出了环形激光器对Ｓ光和Ｐ光相位延迟差与其拍频峰对应的压电陶瓷电压差的关系式,分析了方形环形激光器对Ｓ光和Ｐ 光的频率响应特性,通过测量拍频峰电压差实现环形激光器反射镜相位延迟差测量。通过搭建环形激光器频率响应特性测试系统,从实验上验证了理论计算的正确性。结果表明,该方法测量误差小于１．５％,满足环形激光器反射镜相位延迟差测量要求。     

相移测量技术中相移器研究

本文介绍一种用于相移测量技术的相移器。该相移器由计算机通过Ｄ／Ａ接口板自动控制输出电压幅度，其电路采用闭环控制，位移由压电晶体产生，具有很高的电压稳定度（０１％）和较小的相移误差（小于３°）。描述相移器的结构、驱动源工作原理及相移器标定方法     

A coherent beam combination system based on double PZT phase modulators

A novel coherent beam combination system based on double piezoelectric ceramics transducer (PZT) phase modulators is presented and demonstrated for the first time. In this system, two different PZT phase modulators are used for high frequency phase modulation and low frequency phase control, respectively, while in previous demonstrated system, LiNbO₃ phase modulators are often employed. The inherent low insert loss and high laser-induced damage threshold of the PZT phase modulator makes the new proposed system more compact and stable. By the way, the experiment of coherent beam combination of two 5-W fiber laser beams based on double PZT phase modulators is done. In the experiment, the PZT phase modulator with 500-kHz frequency response point made in home is used for high frequency phase modulating and another one with 0～30-kHz linear frequency response range for phase controlling. When the phase control system is in the closed loop, the fringe contrast of far-field intensity pattern is improved to be more than 90 % from 5 % in open loop.     

电驱动金刚石对顶砧低温连续加压装置

采用电驱动压电陶瓷取代传统机械螺丝给金刚石对顶砧施加压力,设计制备了低温下可连续增加流体静压的金刚石对顶砧压力装置,实现了低温(19±1)K连续加压达到4.41 GPa.该装置具有电驱动方便灵活、调谐精度高的低温连续加压功能.利用该装置实现了InAs单量子点发光与微腔腔模的共振耦合调谐过程.该装置将在原位压力精确调谐及测量样品信号跟踪等实验得到应用.     

强流脉冲驱动的X波段多注相对论速调管相位特性

相位特性是目前制约多注相对论速调管放大器进一步拓展应用的关键参数之一,为了有效提高器件输出微波相位的稳定性,利用一维非线性理论对X波段强流多注速调管放大器开展了理论研究,得到由强流脉冲特性引起的腔体杂频以及电子束运动速度变化率是造成输出微波相位波动的部分主要原因,同时基于18注实心电子束构成的X波段多注相对论速调管放大器开展了强流脉冲特性对输出微波频率和相位影响的数值计算,最后利用粒子模拟手段对理论结果进行验证。理论和模拟结果一致表明:强流脉冲的前沿和波动都将导致器件内实际工作频率的偏移,并引起相位波动;在脉冲前沿段,脉冲前沿长度越短,器件内实际工作频率偏移越大,相位波动幅度越大;在脉冲平顶段,脉冲波动导致的频率偏移与电压变化率相关,与电压的幅值无关,而脉冲电压波动导致的输出微波相位波动由电压变化率及其变化幅度两者共同决定。     

偏置电压对磁致伸缩/压电层合换能结构磁电性能影响

分析和测试了偏置电压调整时PZT5/Terfenol-D/PZT8层合换能结构磁电性能. 提出了一种磁致伸缩/压电层合磁电换能结构的一阶谐振频率控制方法. 通过改变压电驱动层的直流电压对磁电层合结构的预应变进行改变, 从而调整谐振频率. 分析偏置电压、 应变、 弹性模量、 谐振频率和谐振磁电电压系数之间关系. 分析表明: 在较小应变情况下, 控制电压几乎可以线性调节谐振频率, 而层合结构谐振磁电电压系数几乎与偏置电压无关. 实验研究验证: 理论与实验结果较好吻合. 在-170 V-+170 V的偏置电压时, 谐振频率可以几乎线性调整. 最大频率调整量达到1 kHz, 偏置电压对一阶纵振频率的控制率达到: 2.94 Hz/V. 在偏置磁场为0-225 Oe时, 谐振频率调整量与偏置磁场无关. 偏置磁场会改变谐振磁电电压系数, 在大于178 Oe静态磁场偏置时, 磁电电压系数最大, 达到1.65 V/Oe.     

Ultrasonic micro-motor using miniature piezoelectric tube with diameter of 1.0 mm

At the present moment, the smallest piezoelectric ultrasonic micro-motors utilizing miniature PZT piezoelectric ceramic tubes were developed. The motor consists of a PZT-metal composite tube stator, two steel rotors and a thin shaft that keeps the two rotors pressing on both ends of the stator elastically. The dimensions of the PZT tube are 1.0 mm in outer diameter, 0.6 mm in inner diameter and 5.0 mm in length. The diameter and total length of the assembled micro-motor is 1.0 mm and 8 mm (including an adjusting spring), respectively. The tube-type micro-motor is driven by two pairs of alternative voltages with phase shift 90 degrees between the adjacent electrodes and operated in the first circular-bending vibration mode of the stator with the resonance frequency about 58 kHz. The experimental results show that the tube-type micro-motors have perfect performances: (i) high rotation frequency over 3000 rpm and (ii) large starting torque over 7.8 microN m under the conditions of the input voltage of 110 V(p-p) and the resonance frequency. The micro-motor is well suitable for operating in micro-spaces, such as in intravascular, micro-robots and micro-craft applications.     

Advantage analysis of PMN-PT material for free-flooded ring transducers

The acoustic radiation characteristics of free-flooded ring transducers made of PZT4 and PMN-PT materials are calculated and compared.First,the theoretical formulae for free-flooded ring transducers are studied.The resonant frequencies of a transducer made of PZT4 and PMN-PT materials are calculated.Then,the transmitting voltage responses of the free-flooded ring transducers are calculated using the finite element method.Finally,the acoustic radiation characteristics of the free-flooded ring transducers are calculated using the boundary element method.The calculated results show that the resonant frequencies of the free-flooded ring transducer made of PMN-PT are greatly reduced compared with those made of PZT4 with the same size.The transmitting voltage response of the transducer made of PMN-PT is much higher than that of the transducer made of PZT4.The calculated 3-dB beamwidth of the acoustic radiated far-field directivity of the free-flooded ring transducer made of PZT4 at the resonant frequency 1900 Hz is 63.6 and that of the transducer made of PMN-PT at the resonant frequency 1000 Hz is 64.6.The comparison results show that the free-flooded ring transducer made of PMN-PT material has many advantages over that made of PZT4.The PMN-PT is a promising material for improving the performance of free-flooded ring transducers.     

High-precision technique for in-situ testing of the PZT scanner based on fringe analysis

A technique based on fringe analysis is presented for the in-situ testing of the PZT scanner, including the end rotation analysis and displacement measurement. With the interferograms acquired in the Twyman-Green interferometer, the testing can be carried out in real time. The end rotation of the PZT scanner and its spatial displacement deviation are analyzed by processing the fringe rotation and interval changes; displacement of the PZT scanner is determined by fringe shift according to the algorithm of template-matching, from which the relation between the driving voltage and displacement is measured to calibrate the nonlinearity of the PZT scanner. It is shown by computer simulation and experiments that the proposed technique for in-situ testing of the PZT scanner takes a short time, and achieves precise displacement measurement as well as the end rotation angle and displacement deviation measurement. The proposed method has high efficiency and precision, and is of great practicality for in-situ calibration of the PZT scanner.