Tunable Modal Birefringence in a Low‐Loss Van Der Waals Waveguide

van der Waals (vdW) crystals are promising candidates for integrated phase retardation applications due to their large optical birefringence. Among the two major types of vdW materials, the hyperbolic vdW crystals are inherently inadequate for optical retardation applications since the supported polaritonic modes are exclusively transverse‐magnetic (TM) polarized and relatively lossy. Elliptic vdW crystals, on the other hand, represent a superior choice. For example, molybdenum disulfide (MoS₂) is a natural uniaxial vdW crystal with extreme elliptic anisotropy in the frequency range of optical communication. Both transverse‐electric (TE) polarized ordinary and TM polarized extraordinary waveguide modes can be supported in MoS₂ microcrystals with suitable thicknesses. In this work, low‐loss transmission of these guided modes is demonstrated with nano‐optical imaging at the near‐infrared (NIR) wavelength (1530 nm). More importantly, by combining theoretical calculations and NIR nanoimaging, the modal birefringence between the orthogonally polarized TE and TM modes is shown to be tunable in both sign and magnitude via varying the thickness of the MoS₂ microcrystal. This tunability represents a unique new opportunity to control the polarization behavior of photons with vdW materials.     

小型波导传感器单元技术研究

本文提出用梯度有效折射率平面波导形成小型波导传感器的方案 ,对关键单元技术进行了分析和实验 ,给出了结构参数测量结果     

A Compact Fiber-Optic Flow Velocity Sensor Based on a Twin-Core Fiber Michelson Interferometer

A novel fiber-optic flow velocity sensor based on a twin-core fiber Michelson interferometer has been proposed and demonstrated. The sensor only is a segment of twin-core fiber acting as cylinder cantilever beam. The force exerted on the cylinder by the slow flow speeds of order mm/s of the fluid with unknown velocity bends the fiber, which corresponds to the shift of the phase of the twin-core in-fiber integrated Michelson interferometer.     

Ultrasonic Imaging in Hot Liquid Sodium Using a Plate-Type Ultrasonic Waveguide Sensor

This paper reports the first set of results from ultrasonic measurements for determining the imaging capability of a plate-type ultrasonic waveguide sensor in \(200\,^{\circ }\) C liquid sodium. This 10-m long plate-type waveguide sensor has been developed for viewing objects in opaque liquid sodium coolant for the applications in a sodium-cooled fast reactor (a next generation nuclear reactor). Various imaging capabilities of the waveguide sensor have already been demonstrated in water including ultrasonic beam steering, high resolution C-scan, and so on. However, water and liquid sodium have different acoustic properties and, more importantly, different wetting characteristics with stainless steel—the material for the waveguide sensor. For applications of the developed waveguide sensor in a real reactor environment, this research performs a set of necessary ultrasonic measurements in liquid sodium. The end section of the waveguide sensor which radiates an ultrasonic beam into the liquid sodium is coated with thin beryllium and nickel layers which can significantly improve the ultrasonic beam quality and wetting property of the stainless steel. A liquid sodium facility that consists of a glove box system, a sodium test tank, and an argon purification system has been built. The resolution and beam property are determined from ultrasonic C-scan experiments; a signal-to-noise ratio of over 10 dB and the resulting detection of a 1 mm wide slit can be achieved. The inherent issues associated with wetting of the waveguide sensor in liquid sodium are discussed based on the ultrasonic imaging results.     

双Fabry-Perot干涉纳米测量控制系统的设计

设计了一种基于双Fabry-Perot干涉仪的新型纳米测量系统,阐述了系统各环节的数学模型。针对探针与样品表面相互作用的数学模型比较复杂的特点,详细设计了基于模糊控制理论的控制系统,提出了通过控制控针振动曲线不变进行纳米测量的理论依据及实测方法。在此基础上,对系统进行了仿真实验,实验结果充分证明了系统设计及理论依据的正确性。     

包层腐蚀光纤M-Z干涉型高灵敏度折射率传感器(英文)

我们设计并制作了一种基于Mach-Zehnder干涉的高灵敏折射率传感器,其结构由两个光纤纤芯偏移的熔接结经包层腐蚀后组成。首先,利用商用的光纤熔接机在单模光纤上制作两个光纤纤芯偏移的熔接结;然后,将光纤化学腐蚀获得细薄的光纤包层,则光纤倏逝场与周围介质强烈相互作用,即制作出Mach-Zehnder干涉型高灵敏折射率传感器。实验结果表明,制作的长度为10 mm、直径为13.2μm的Mach-Zehnder干涉型折射率传感器,在折射率1.333～1.3685和1.3685～1.386范围内,其传感灵敏度分别高达1288.05和2118.26 nm/RIU。该传感器具有高灵敏度、结构紧凑、制作简单和低成本的优势。     

Fiber-Based White-Light Interferometer With Improved Sensor Tip and Stepped Mirror

White-light interferometry has been a well-known and established measurement technique for years. However, in certain fields of production technology, such as microassembly or small-cavity inspection, there is a need for miniaturized metrology systems. This request can be answered, among other variants, with the use of fiber-based interferometry. The application of fibers enables, e.g., separation of a sensor (probe) from an optical receiver. The result is that the sensor probe can theoretically be miniaturized down to the curve diameter of the used fiber. On the one hand, this paper demonstrates how the use of a continuously improved miniaturized sensor probe can enable the application of such a measurement system in the mentioned technological fields. On the other hand, it describes the present state of a special mirror to increase the measuring range, frequency, and stability of the sensor system. This mirror replaces the moving reference mirror, which is commonly needed in an interferometer. It is designed with a certain number of steps to compensate the path difference between the object and reference beams. The fundamental aspects of white-light interferometry are presented and lead to the concept of a miniaturized fiber-based distance-measurement system.     

纳米级二维激光外差干涉仪的设计

提出了一种５０μｍ测量范围内，２ｎｍ不确定度，、０．５ｎｍ分辨率的二维激光外差偏振干涉仪的设计。其中用声制器和稳频Ｈｅ－Ｎｅ激光器获取频差小于２００ｋＨｚ的正交偏振双频激光束，Ｘ和Ｙ二臂偏振干仪将采用差分干涉仪，采用相位解调技术进行外差干涉信号的处理。     

一种四分量测力传感器的设计

多分量传感器的需求场合越来越广泛,但大多数的多分量传感器各个分量之间输出量的影响都不是很理想。文章比较详细介绍了一种铣床上用四分量传感器的设计、贴片和组桥及详细的测试数据,这种四分量传感器通过合理的贴片和组桥,比较好地解决了各个分量之间的交叉影响量。     

光子晶体光纤F-P干涉式高温传感器研究

本文提出一种用于高温测量的光子晶体光纤F-P干涉传感器,通过熔接机放电使无截止单模光子晶体光纤(ESM-PCF)一个端面完全塌陷,然后再将其与单模光纤(SMF-28e)熔接起来,最后按照设计长度切断ESM-PCF。由于在熔接点处ESM-PCF完全塌陷使其模场直径扩大,减小了与SMF-28e的模场失配损耗,并提高了熔接面的反射光强。这种方式制作简单,相对于以往的光子晶体光纤F-P干涉传感器具有更高的干涉光强度。实验结果表明,该传感器测量温度可达1100℃,温度灵敏度为29.4nm/℃,可以预见这种结构稳定、线性度好的全光纤传感器在机械、航空、冶金领域等具有一定的潜在应用价值。     

一种指尖三维力传感器设计

设计了一种用于仿人灵巧手的指尖三维力传感器,采用十字梁与中心直梁相结合的结构实现对三维力的感知。首先利用ANSYS工具对设计的十字梁弹性体进行静力学分析,通过分析对弹性体的结构尺寸进行了优化,并给出了最佳贴片方案;最后对设计的指尖三维力传感器进行静态标定试验,建立了维间耦合误差模型,利用静态解耦算法对传感器耦合误差进行解耦计算,有效提高了指尖三维力传感器的测量精度。实验结果表明:设计的三维指尖力传感器的测量精度优于2.5%。     

浮筏隔振装置设计中的模态控制研究

对安装有三台机组的大型复杂浮筏隔振系统进行研究.对筏体和浮筏隔振系统进行了有限元建模.接着对各种支撑条件下的筏体和完全组装好的筏体进行了模态测试和分析,得到了筏体在不同状态下的模态参数并对其进行了比较.结果表明从模态控制的角度来看筏体设计是成功的.     

一种新型光纤电流传感器的设计

本文提出了一种新型的高压电流光纤传感器 ,该系统由具有相位压缩原理的Sagnac干涉仪光路构成 ,与通常的干涉仪相比该系统的动态测量范围扩大数百倍 ,而且系统不受外界缓变量的影响 ,系统采用相位切换技术使干涉仪保持在正交干涉状态     

纳米多孔光波导漏模共振传感器的折射率灵敏度分析(英文)

在玻璃基片上射频溅射50 nm厚的金膜,然后利用TiO2胶体溶液在金膜表面制备了厚度约为320 nm的TiO2纳米多孔薄膜.以此双层膜为漏模光波导芯片,构建了基于Kretschmann结构的波长调制型光波导漏模共振(LMR)传感器.利用扫描电子显微镜(SEM)观测了TiO2纳米多孔薄膜的表面和横截面形貌.实验研究了在纳米多孔光波导中给定漏模的共振波长及折射率灵敏度与入射角的依赖关系.结果表明,随着入射角的增大,共振波长逐渐蓝移,折射率灵敏度随之下降.此外,与传统的表面等离子体共振(SPR)传感器进行了对比,结果表明在相同的共振波长下,纳米多孔光波导LMR传感器折射率灵敏度大于SPR传感器.     

具有力传感器的纳米加工探针的设计

给出了一种用于复杂表面形状精密纳米加工的探针装置．该探针由一个高速可控的金刚石切割单元（FTC单元）和一个高灵敏度的压电式力传感器组成．而FTC单元由一个单点金刚石切割工具和一个压电陶瓷晶体（PZT）驱动器构成．压电陶瓷晶体（PZT）驱动器可对与切削量相对应的金刚石工具的Z向位置进行高速控制,从而实现加工复杂表面形状的目的．加工中的切削力是反映切削进程的重要指标,可由联结于FTC单元的高灵敏度力传感器进行测量．比对了用于联结力传感器和FTC单元的两种设计方法．     

激光干涉仪误差修正系统的设计

基于谐波分离修正算法,采用高速可编程器件,构建了一套激光干涉仪误差修正系统.该系统通过校准过程建立误差修正方程,并生成修正相位表.测量时数据采集及处理单元的可编程器件实现定点型移位相减除法运算,得到数字化的正切值,将正切值作为内存地址,通过硬件查表得到修正相位值,极大提高了误差修正速度.并分析了定点型移位相减除法精度以及寻址空间大小对系统误差的影响.     

一种EFPI光纤压力传感器的结构分析及零点稳定性

介绍了一种基于法布里-珀罗干涉原理的EFPI光纤压力传感器。详细分析了这种光纤压力传感器的原理、结构和解调方法;讨论分析了材料、结构以及制作工艺对零点稳定性的影响;探讨了传感器内部热应力的分布以及消除方法。该结构传感器在经历-40℃和400℃的严酷温度考验后,零点漂移小于3 nm。     

弧型波导全光开关的优化设计

应用光束传输法对基于三阶非线性材料的弧型波导全光开关的开关特性进行了模拟,对两波导中心距、宽度及其不对称性等几何参数对开关特性的影响进行了分析,并对其进行了优化设计。结果表明,优化设计后的弧型波导全光开关具有较低的平均开关功率、数值化多次开关特性,有着弱光非线性全光开关的应用前景。     

基于相移干涉仪的平面度测量软件设计

以相移干涉法测出的点阵波面数据为基础,设计了计量用平面度测试软件Flat Ex,包括标准平晶的绝对检验、研磨面平尺的斜入射测量和子孔径拼接及三个功能算法模块。通过与等倾干涉仪检定过程的比较,从理论上说明从密集点阵数据中提取稀疏点数据的合理方法,以符合规程的要求或约定俗成的做法。程序已经用于处理Matro Pro和Phase One等多种相移干涉仪数据,提取出符合要求的平面度结果。在相移干涉仪与等倾干涉仪检定结果进行比对实验中,表现出良好的一致性。