基于复合静电驱动结构的硅微机械扭转微镜

为了改善硅微机械扭转微镜的机电耦合特性,降低器件的驱动电压并提高其工作可靠性,提出了几种新颖的基于复合静电驱动结构的硅微机械扭转微镜.提出的硅微机械扭转微镜将垂直扭转梳齿静电驱动结构、侧壁平行板电容静电驱动结构有机结合,实现了两种静电驱动方式的复合驱动,同时设计了内外双镜面结构,通过内外双镜面结构,实现了微镜的差动复合驱动,理论分析、模拟仿真与测试结果表明,通过上述两个方面新颖的设计,新结构显著降低了器件的驱动电压.同时为了提高器件的工作可靠性,在设计折叠梁柔性支撑结构时,将梁的不同位置设计成不同的厚度,对于硅微机械扭转微镜扭转过程中容易疲劳的梁部分加大了其厚度,从而在不影响器件扭转性能的前提下,明显提高了器件的可靠性.利用有限元方法对器件的力学特性和机电耦合特性进行了系统的仿真,获得了影响器件机电特性的关键结构参数.器件基于SOI晶片,采用表面硅工艺与体硅工艺相结合的方式加工制造,采用SOI晶片显著降低了微镜镜面的表面粗糙度,提高了其光反射能力.最后利用原子力显微镜对微镜镜面的表面粗糙度进行了测量和分析,实验结果表面微镜表面具有16nm的表面粗糙度,完全可以满足光学应用的需要.     

大视场数字式太阳敏感器设计

提出了一种新型的大视场数字式太阳敏感器设计方法,其光学系统由全景环形光学镜头和滤光膜组成.该敏感器具有视场大、结构简单及功耗低的特点.从工作原理出发,建立了该敏感器模型,并利用搭建的实验平台,对敏感器进行精度标定.设计中,采用非线性最小均方最优解来确定模型中的参数.对测量误差进行分析,消除系统误差后,敏感器的测量精度由...     

一种新型谐振式MOEMS陀螺的设计及分析

提出一种新型的利用空间光路敏感Sagnac效应的谐振式MOEMS陀螺,设计了利用微镜构成的光学谐振腔.此结构具有小型化优势,可利用MOEMS工艺进行加工.理论分析了光源及谐振腔参数对陀螺基本探测极限的影响,指导参数设计,得到陀螺的极限灵敏度为1.54°/h.通过模式匹配理论对谐振腔型式进行了改进,减小了谐振腔损耗.进行了谐振腔原理验证实验,观察到谐振曲线.最后对微谐振腔的加工工艺进行了讨论.     

基于永磁薄膜的MEMS磁传感器设计与制作

提出了一种基于永磁薄膜的新型MEMS磁传感器,磁传感器由MEMS扭摆、CoNiMnP永磁薄膜和差分检测电容等部分组成。分析了磁传感器的磁敏感原理和电容检测原理,提出了器件的结构参数并对器件进行了模态仿真。利用MEMS加工技术成功制作了MEMS磁传感器样品,并进行了测试。测试结果表明:得到的MEMS磁传感器的电容灵敏度可达到27.7 fF/mT,且具有良好的线性度。根据现有的微小电容检测技术,传感器的磁场分辨率可达到36 nT。     

一种基于感声波纹结构的光学式声传感器

设计了一种基于硅MEMS敏感结构的光学式声传感器,其光学调制原理采用强度调制型,微敏感结构采用具有低应力波纹结构的感声薄膜芯片。对光纤与微敏感结构耦合技术进行实验研究,优化光学参数,并制作传感器样品。经实验测试,灵敏度达80mV/Pa。     

用于远距离测速的光纤准直器研究

为了在空气炮内弹道测速中提高光纤准直器的工作距离,对光纤准直器结构进行改进,以实现远距离探测。列举了几种常见的准直透镜。从高斯光束原理以及可实现光学探测工作距离的角度出发,在C-LENS透镜原理基础上,提出了直径为16 mm的空气炮弹丸测速装置,并设计了长距离光纤准直器。在ZEMAX软件中对准直器进行仿真,利用优化函数求出透镜最大工作距离,并通过光束质量分析仪检测准直器性能指标。仿真结果进一步验证了准直器的可行性。通过在导轨上进行长距离返回光耦合效率试验,证明了该设计基本满足10~1 500 mm的探测要求,为光纤准直器的长距离测量提供了技术参考。     

常压封装下隧道磁阻微陀螺的高灵敏结构设计

针对现有微陀螺难以实现常压封装下高灵敏检测的难题,设计了两种应用隧道磁阻效应检测的微陀螺结构,分别采用面内检测与离面检测,本文从阻尼与检测磁场两方面对二者性能进行分析。首先通过对二者阻尼的计算,得到常压下面内检测结构的灵敏度为35.18 nm/(°/s),离面检测结构的灵敏度为3.19 nm/(°/s),面内结构比离面结构的灵敏度高约10倍,从阻尼方面考虑,采用面内检测的结构更优;其次设计了应用于两种结构中的检测磁场,得到了面内检测磁场相比于离面检测磁场具有更高的磁场变化率,更好的磁场一致性,从磁场方面考虑,同样得到面内检测的微陀螺结构更优。因此,应用面内检测结构可以实现隧道磁阻微陀螺在常压下的高灵敏检测。     

基于NEMS技术的硅基纳机电探针阵列器件研究

进行一种用于高密度存储的硅基纳机电探针阵列器件研究.并采用理论计算和有限元模拟相结合方法对器件进行了设计;使用先进的微纳加工工艺技术将压阻敏感器和电阻加热器集成到超薄悬臂梁-针尖结构纳机电探针阵列器件上,实现器件制作;随后,进行器件电热特性及其敏感特性测试,测试结果与模拟结果相吻合;借助于原子力学显微镜在聚合物有机薄膜上实现了数据写入,优化写入条件后,数据记录面密度达31.6 GB/in2.     

面向微小卫星的星敏感器研究

研制了一款新型面向微小卫星的星敏感器,采用商用器件构成以满足微小卫星对小型化的要求.星敏感器由工业镜头、DSP、低功耗CPLD和灰度型CMOS图像传感器组成.为进一步提高测量精度以满足卫星的需求,针对星敏感器的成像模型进行了分析,并用恒星校准的方式补偿了光学参数;对恒星处理算法进行了分析,在图像处理环节特别地采用了中值滤波技术,解决了孤立脉冲噪声对星点提取的影响.基于地球自转的星座跟踪实验表明,所研制的星敏感器样机欧拉角回归标准差为30″,已可实际应用于微小卫星平台.     

光学敏感器及元件

我所的光学敏感器研究室,技术力量雄厚,设备齐全。多年来从事高精度,高可靠光学敏感器的研究。其产品已成功地用于我国的科学技术卫星和实验通信卫星上。我们乐意为其它用户提供有关产品及其周到服务。1.光学零件、光学复制转移膜、增透膜及红外带通滤光片。2浸没型热敏电阻红外探测器、薄膜热电堆及其它薄膜传感器。3.红外及可见光检测、识别、定向系统及其装置。4.CCD 器件应用。下面介绍该室的部分产品。     

Microfluidic MEMS-Based Light Modulator Using Magnetic Fluid Suitable for Flat Panel Display Applications

A new microfluidic MEMS-based light modulator using magnetic fluid is introduced. The device has a planar structure that makes it suitable for being produced with conventional thin-film processes and for being used in flat-panel displays (FPDs). The optical reflectance from the device is modulated by applying an electric current into an electrode. The magnetic field produced by the current exerts a magnetic force on the magnetic fluid and drives it to cover the cell surface. The surface tension of the fluid provides a restoring force when the field is reduced. A permalloy based thin-film process developed for the manufacturing of inductive head for magnetic data storage devices was used for the device fabrication. The actuation of the fluid is completed in about 12 ms for both thin-to-thick and thick-to-thin fluid film switching by magnetic forces and surface tension forces, respectively. It was observed that the switching speed was almost independent of the driving current, and no considerable thermal effect has been observed when driven by a current up to 100 mA.hfillhbox[1227]     

Magnetic-fluid core optical fiber

We report the first fabrication of magnetic-fluid core optical fiber (MFCOF). Paraffin-based magnetic fluid is selected as the liquid and filled in a hollow core fiber with the core-diameter of 5 μm and the length of 20 cm. The optical properties of MFCOF were investigated by sending light into them. The wires allow multi-mode operation, and have an optical loss less than 0.6 dB/cm. In contradiction to the traditional liquid core optical fiber, the optical properties of MFCOF can be tunable under the external magnetic field, which may find applications in device physics on combined fields of magnetic fluid and nonlinear fiber optics.     

Latching micromagnetic optical switch

In this paper, we report a new type of latching micromagnetic optical switch. The key component of this optical switch is a cantilever made of soft magnetic material with a reflective surface serving as a mirror. The cantilever has two stable positions, therefore two stable states for the device, with presence of an external magnetic field. Input optical signal to the device is switched selectively to one of the two output ports when the device transitions between the two states upon short electromagnetic actuations. The optical switch is bistable because the cantilever has a tendency to align with the external magnetic field, and the torque to align the cantilever can be bidirectional depending on the angle between the cantilever and the magnetic field. Switching between the two stable states is accomplished by momentarily changing the direction and/or the magnitude of the cantilever's magnetization by passing a short current pulse through a planar coil underneath the cantilever. In either of its stable state, the cantilever is held in position by the combined influence of the static external magnetic field and mechanical force, such as from a physical stopper or a mechanical torque produced by the torsion flexures supporting the cantilever. Stable vertical position for the cantilever is obtained by using a tilted external magnetic field. When the cantilever mirror is at this UP state, light is reflected to the desired output port. Large angle deflection and bistable latching operations have been demonstrated. The measured mechanical switching speed between the two states of the prototype is 3.2 ms. Optical insertion loss is -4 dB, and the energy consumption is 44 mJ for each switching event.     

A new scanning MEMS mirror

This paper introduces the development of a new MEMS-based optical mirror, which performs optical scanning function with discrete reflection angles in an out-of-plane configuration. The device was fabricated through Deep Reactive Ion Etching (DRIE) process on silicon-on-insulator (SOI) wafer, followed by assembly with two metalised glass dies. The optical mirrors can be tilted by electrostatic forces between the opposite electrodes on the SOI and glass dies. The most outstanding performance that can be expected from the device is the discrete and therefore, reliable tilting angle of the mirror, which is guaranteed by its unique mechanical structure and the electrostatically driven mechanism. In this paper, the working principle of the new MEMS mirror was presented, followed by the introduction of device design, mechanical simulation, microfabrication process, assembly solution, and some testing results. The potential application of this new MEMS mirror is for light beam scanning or optical sensing (detection).     

High responsivity silicon MOS phototransistors

We describe a metal-oxide silicon (MOS) phototransistor that relies on a novel lateral doping scheme that creates a p-i-n junction configuration for light detection. This is essentially a hybrid device with the horizontal structure of a p-i-n diode and the vertical structure of a MOS field-effect transistor. The lateral p-i-n diode detects light whereas the gate can be used to change the current flowing through the device; making it appear as a MOSFET. This feature makes it easy to integrate it with other conventional MOSFETs on a CMOS process flow. The device shows high optical responsivities that persist to wavelengths in the near-ultraviolet region. The fabrication of the device as well as its electrical and optical characteristics is described.     

Cs光泵磁强计补偿地磁变化的方法

在弱磁测量技术当中,往往需要在一定的工作空间区域内获得稳定的磁场。光泵磁强计具有高灵敏度、高分辨力的优点。主要介绍使用光泵磁强计补偿地磁感应温度的原理、设备组成及实验。根据锁相环原理,利用Cs光泵磁强计和线圈系统把地磁感应强度的波动补偿到小于0.1nT,可以获得稳定度很高的恒定磁场空间。恒定磁场空间可以用来校准磁通门磁强计和其它磁传感器。     

MATLAB-based program for optimization of quantum cascade laser active region parameters and calculation of output characteristics in magnetic field

A strong magnetic field applied along the growth direction of a quantum cascade laser (QCL) active region gives rise to a spectrum of discrete energy states, the Landau levels. By combining quantum engineering of a QCL with a static magnetic field, we can selectively inhibit/enhance non-radiative electron relaxation process between the relevant Landau levels of a triple quantum well and realize a tunable surface emitting device. An efficient numerical algorithm implementation is presented of optimization of GaAs/AlGaAs QCL region parameters and calculation of output properties in the magnetic field. Both theoretical analysis and MATLAB implementation are given for LO-phonon and interface roughness scattering mechanisms on the operation of QCL. At elevated temperatures, electrons in the relevant laser states absorb/emit more LO-phonons which results in reduction of the optical gain. The decrease in the optical gain is moderated by the occurrence of interface roughness scattering, which remains unchanged with increasing temperature. Using the calculated scattering rates as input data, rate equations can be solved and population inversion and the optical gain obtained. Incorporation of the interface roughness scattering mechanism into the model did not create new resonant peaks of the optical gain. However, it resulted in shifting the existing peaks positions and overall reduction of the optical gain.     

Transflective blue‐phase liquid‐crystal display with corrugated electrode structure

Abstract— A transflective polymer‐stabilized blue‐phase liquid‐crystal display (BP‐LCD) with a corrugated electrode structure is proposed. To balance the optical phase retardation between the transmissive (T) and reflective (R) regions, two device structures are proposed. The first device structure has the same inclination angles but different cell gaps in the T and R regions. And the second device structure has the same cell gap but different inclination angles in the T and R regions. Both of the device structures can obtain well‐matched VT and VR curves. This display exhibits low operating voltage, high optical efficiency, and a wide viewing angle.     

光纤通信系统中的光检测器件

论文介绍运用在光纤通信系统中的光检测器件的结构、工作原理及性能,并对PIN和APD两种光检测器件进行了比较。     

Structural optimization in magnetic fields using the homogenization design method — Part I

Summary The homogenization design method has been successfully applied to obtain the optimal topology of a structure under electrical fields as well as various mechanical environments. This paper introduces the expansion of the application of the homogenization design method into the structure in magnetic fields. The topology optimization on a device in magnetic fields is focused on the maximizing the magnetic flux in an air-gap. This is accomplished by maximizing the magnetic mean compliance defined by the magnetic energy in a given region of the device. The homogenization design method is applied to three-dimensional cases with and without considering the saturation effect of the material. Results show that the homogenization design method is valid to maximize the vector potential in linear cases and the magnetic flux in non-linear cases.