基于超薄钽酸锂晶体材料高响应太赫兹探测器（英文）

太赫兹(Thz)探测器工作在室温条件下极大地促进了太赫兹科学与技术的应用。超薄(10μm)钽酸锂(LiTaO_3)晶片被用作太赫兹探测器敏感元材料。基于钽酸锂晶片太赫兹探测器在2.52 THz激光辐射源照射下,20Hz斩波频率时响应率可达到8.38×10~4V/W,等效噪声功率NEP)可达到1.26×10~(-10)W。这种加工超薄钽酸锂晶片的方法为制备高响应率太赫兹探测器提供了一个可行的方法。     

基于钽酸锂晶片的太赫兹热释电探测器

针对自由空间和波导传输太赫兹辐射功率兼容测试的需求,开展了光敏面直径为10 mm的多功能太赫兹热释电探测器的相关研究。通过有限元分析及热电耦合仿真设计,建立了敏感元件由100 μm 厚的钽酸锂（LiTaO₃）晶片和碳纳米管吸收层组成的太赫兹热释电探测器模型;采用优化的精确减薄抛光和剥离等关键工艺,重点攻克了采用大晶片多阵列方式制作LiTaO₃基太赫兹热释电探测器敏感元件的工艺难题,并完成了太赫兹热释电探测器的研制。在设定条件下,该探测器的响应度为371.8 V/W,噪声等效功率为0.34 nW/Hz^1/2。实验结果表明,设计并制作的太赫兹热释电探测器的集成度高、响应度良好、噪声等效功率低,能够有效解决大光斑太赫兹光束功率测试问题。     

蝶形天线增强的HEMT室温太赫兹探测器

介绍了一种基于GaN/AlGaN高电子迁移率晶体管(HEMT)的高速、高灵敏度室温太赫兹探测器。在太赫兹波辐射下,HEMT源漏端产生直流光电流,并能被栅压灵敏地调控。探测器中新颖的蝶形天线设计使接收到的太赫兹电场得到显著增强,提高了探测器的响应度。通过测量探测器对不同偏振方向的太赫兹光的响应,有效验证了蝶形天线对太赫兹电场的增强作用。室温下,探测器的等效噪声功率约为5×10-10W/Hz21,平均响应度达42mA/W。实验结果表明,光电流的产生与二维电子气沟道的场效应特性和入射太赫兹波电场在电子沟道中的分布密切相关。自混频理论能很好地描述实验结果。     

钽酸锂薄膜红外探测器探测性能的模拟研究

建立了热释电钽酸锂薄膜红外探测器理论模型,用五层薄膜系统模拟了探测器结构,用钽酸锂晶体参数,模拟了探测器结构参数与探测率等性能指标之间的关系,研究了硅衬底厚度和钽酸锂薄膜厚度对探测器性能的影响。模拟结果显示,硅衬底彻底腐蚀形成悬空结构是减小探测器热传导损耗的最有效途径;热释电钽酸锂膜层越薄,器件探测率越高。探测器电压响应同时取决于钽酸锂膜层厚度和探测器外接电路参数。使探测器整体性能最佳的钽酸锂膜层厚度为1～2μm。     

基于石墨纳米材料的电磁诱导势阱效应的室温太赫兹探测研究

基于石墨纳米材料,成功制备金属-石墨-金属结构电磁诱导势阱效应室温太赫兹探测器,实现了高性能的室温太赫兹探测。器件在0.035 THz的响应率达到20 kV/W,在0.1673 THz的响应率达到11 kV/W,器件在0.035 THz的噪声等效功率达到1.25 ,在0.1673 THz的噪声等效功率达到2.27 。我们的研究结果为石墨烯太赫兹探测器提供新的思路。     

基于65 nm标准CMOS工艺的3.0 THz 探测器

基于Dyakonov和Shur等离子体波振荡原理设计并流片制备了一种采用65 nm标准CMOS工艺的3.0THz探测器,探测器包括贴片天线、NMOS场效应晶体管、匹配网络及陷波滤波器。探测器在室温条件下可达到526 V/W的响应率(Rv)和73 pW/Hz1/2的噪声等效功率(NEP)。采用该探测器和步进电机搭建了太赫兹扫描成像系统,获得了太赫兹源出射光斑的远场形状,光斑的半高宽(FWHM)为240μm;并对聚甲醛牙签和树叶进行了扫描成像实验,结果表明CMOS太赫兹探测器在成像领域有潜在的应用前景。     

基于石墨烯/砷化镓异质结构的毫米波/太赫兹探测器

单层石墨烯具有较低的固有光吸收效率,且材料中含有较多的缺陷,导致仅依靠石墨烯本身很难制备高性能的光电器件。通过石墨烯与半导体材料复合形成异质结构的方法可以克服这一瓶颈。本工作中利用石墨烯/砷化镓高迁移率异质晶体管结构制备了毫米波光电探测器,有效地提升了二维电子气特性,大幅度提高了器件在室温条件下的毫米波响应和探测能力。实验证明,400 mV的偏置电压下,该器件在25 GHz波段的获得了20.6 V?W^-1响应率,响应时间为9.8 μs,噪声等效功率为3.2×10^-10 W?Hz^-1/2。在太赫兹波0.12 THz下响应率仍然达到了4.6 V?W^-1,响应时间为10 μs,噪声等效功率为1.4×10^-9 W?Hz^-1/2。该工作展示了石墨烯/砷化镓异质结构毫米波太赫兹探测器的巨大应用前景。     

离子束研磨的高探测率热电探测器

用离子束研磨工艺制备了薄达4微米的可自身支持的热电材料片。用这些极薄的片子制备了1毫米~2的钽酸锂探测器,其归一化探测率D~*经测量为8.5×10~8厘米。赫~(1/2)。瓦~(-1)(30赫)。用这种工艺有可能做出的探测器D~*大大超过10~9厘米·赫~(1/2)·瓦~(-1)。此外,离子束磨片还具有清洁、表面无损伤的优点,且可获得几何结构复杂的探测器片子。     

基于金属-半导体-金属结构的Bi2Te3室温高响应率太赫兹探测器

基于二维拓扑绝缘体Bi_2Te_3材料利用微纳工艺制备了金属-拓扑绝缘体-金属(MTM)结构的太赫兹光电探测器.器件在0. 022 THz的响应率可达2×10~3A/W,噪声等效功率(NEP)低于7. 5×10~(-15)W/Hz~(1/2),探测率D~*高于1.62×10~(11)cm·Hz~(1/2)/W;在0. 166 THz的响应率可达281. 6 A/W,NEP低于5. 18×10~(-14)W/Hz~(1/2),D~*高于2. 2×10~(10)cm·Hz~(1/2)/W;在0. 332 THz的响应率可达7. 74 A/W,NEP低于1. 75×10~(-12)W/Hz~(1/2),D~*高于6. 7×10~8cm·Hz~(1/2)/W;同时器件在太赫兹波段具有小的时间常数(7～8μs).该项工作突破了传统光子探测的带间跃迁,实现了可室温工作、高响应率、高速响应以及高灵敏度的太赫兹探测器件.     

HEMT太赫兹探测器响应度和NEP的检测与分析

在0.8～1.1 THz内,对AlGaN/GaN高电子迁移率晶体管(HEMT)太赫兹探测器的响应度和噪声等效功率进行了具体测试和分析。在太赫兹波辐射下,HEMT太赫兹探测器源漏端产生能被栅压灵敏调控的直流光电流。该型探测器在300 K和77 K下的电流响应度分别为83 mA/W和4.1 A/W,电压响应度分别为4 kV/W和50 kV/W,噪声等效功率分别达到22 pW/Hz0.5和1 pW/Hz0.5。采用两种较为典型的测量方法,通过对实验结果的比较,确定了影响该类型探测器的响应度和噪声等效功率的主要因素,并提出了增强响应度和降低噪声等效功率的具体措施。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks