双波泵浦量子阱子带共振跃迁的非线性光学性质

设计了组分为Al_(0.5)Ga_(0.5)As/GaAs/Al_(0.2)Ga_(0.8)As阶梯形量子阱结构,其导带子带能级可与中红外双波长CO_2激光器的泵浦光光子能量共振.计算了此量子阱对两束泵浦光的二阶非线性差频系数χ_(DFG)~((2))及三阶非线性系数χ_(ω1)~((3))和χ_(ω2)~((3))的表达式;在导带分别为抛物线形和非抛物线形两种条件下,对比研究了三个非线性系数随两束泵浦光波长的变化.χ_(DFG)~((2))、χ_(ω1)~((3))和χ_(ω2)~((3))随两束泵浦光波长λ_(p1)和λ_(p2),都是呈现出先增大后减小的变化趋势,对应不同泵浦波长,存在一个峰值;相比于导带为抛物线形,在非抛物线条件下三个非线性系数随短波长的泵浦光λ_(p1)的变化出现"红移"现象,而随长波长的泵浦光λ_(p2)的变化峰值位置基本相同;由量子限制效应导致的两种导带情况下子带能级变化,即与泵浦光光子共振条件发生变化,是出现"红移"的原因;而峰值数值上的差异,主要由量子阱子带能级间的跃迁矩阵元和两种导带条件下不同的能级差决定.     

MCT液相外延薄膜的生长和特性

用开管水平液相外延系统从富Te溶剂中生长了不同x值的MCT薄膜。经X射线衍射、Hall电学参数、红外光谱、扫描电镜、X射线能谱仪和电子通道花样分析测试,结果表明:外延薄膜表面平整,光学参数较好,纵向、横向组份均匀,晶体结构完整,电学参数较好,外延膜质量优良。短波材料(n型):载流子浓度3.54×10~(14)cm~(-3),迁移率1.63×10~4cm~2V~(-1)s~(-1);中波材料(n型):载流子浓度9.95×10~(14)cm~(-3),迁移率为1.76×10~4cm~2V~(-1)s~(-1);原生长波材料(n型):载流子浓度为2.15×10~(15)cm~(-3),迁移率2.00×10~4cm~2V~(-1)s~(-1)。     

单晶薄膜体声波谐振器频率温度特性研究

采用离子注入剥离法转移制备了43°Y 切铌酸锂(LiNbO3,LN)单晶压电薄膜材料,以SiO2/Mo作为声反射结构制备了固态声反射型薄膜体声波器件。谐振器工作频率约为3 GHz,LN薄膜等效机电耦合系数达到14.15%。对谐振器的频率温度特性进行了表征,结果表明,尽管LN单晶的频率温度系数为(-70~-90)×10-6/℃,但由于声反射结构中包含有正温度系数的SiO2层,谐振器的频率温度系数降至-18×10-6/℃,这表明固态声反射结构能够有效抑制单晶LN薄膜的温漂,获得低频率温度系数的谐振器器件。     

知识介绍

微波加热物体能量关系式的推导利用微波能对介质进行加热已得到广泛的应用。这里就人们常用的能量关系式作一推导,以帮助人们正确的应用它。对于非完纯介质中可能存在的损耗用其导磁率和介质常数来表示: μ=μ′-iμ″,(1) ε=ε′-iε″,(2)一般介质情况下可以忽略μ″。假若介质中还存在欧姆损耗,则损耗电流密度为 =σ (3)σ是介质的电导率。时谐场的平面电磁波可写作 = e~(((iω)-r()) (4)其中_0和_0是起始时电场幅值,γ是传播常数γ=(iωμ(σ iωε))~(1/2) (5)令γ=α iβ,并考虑(1)、(2)及(3)可得α=ω((μe′)~(1/2))/2 ((1 ((σ (ωε)″)/(ωe)′)~2-1)~(1/2))~(1/2) (6) β=ω((μe′)~(1/2))/2 ((1 ((σ (ωε)″)/(ωe)′)~2 1)~(1/2))~(1/2) (7)α,β值可用来确定有损耗介绍中电磁波的渗透和衰减。另外,波印亭能流密度矢量为 =× (8)对于通过封闭面S的总能流为∮_s··ds (9)式中是表面的单位法矢量。利用奥高定理∮_s·ds=∫_F▽·dV及▽·(×)=·▽×-▽×,并考虑▽×=-()/(t),▽×=J ()/(t),=μ及=ε则可以推得     

碲镉汞光导探测器与材料性能关系探讨

本文有针对性地考察了碲镉汞3～5μm12元光导探测器平均电阻R与材料电阻率ρ的关系。碲镉汞材料主要用快速淬火固态再结晶法生长,为与其比较,也少量使用了T_e熔剂和布里奇曼法料。退火的晶片厚度约1mm,77K霍尔数据表明,N型材料占被统计数(122片)的88%,材料参数多数为n=8×10~(14)～8×10~(15)cm~(-3)、μ=1×10~3～5×10~4cm~2/     

热处理对TaN薄膜电性能的影响

采用直流磁控溅射法在Al2O3陶瓷基片上制备了TaN薄膜,研究了热处理温度和时间对TaN薄膜的方阻(R□)及电阻温度系数(TCR)的影响。研究发现,在热处理时间为2h的条件下,热处理温度在200℃到600℃变化时,R□从12?/□增加到24?/□,TCR从15×10-6/℃下降到-80×10-6/℃;在热处理温度为300℃的条件下,热处理时间对R□及TCR影响较小,随着热处理时间的增长,R□及TCR略有变化。     

R—600瓷料的试制

以BaTiO_3为基的BaTiO_3-La_2O_3·2TiO_2-SrTiO_3系统的R—600瓷料,性能稳定,介电常数ε≥750,介电常数温度系数α_c为-(4700±800)×10~(-6),介质损耗为(3～5.5)×10~(-4),抗电强度≥8KV/mm,比体积电阻为10~(12)Ω·cm以上,是生产小体积、高电压电容器的较为理想的陶瓷材料。 本文较详细地叙述了该陶瓷材料的配方试验、工艺探索及试验结果。     

核泵浦~3He-Ne激光增益实验

在稳态核反应堆上,测定了热中子辐照下,~3He-Ne激光体系(P_(He:P_(Ne)=5:1,P_总=4×10~4Pa)的增益系数(丸=632.8nm,跃迁3S_2-2P_4)。当热中子通量为2×10~(12)n/cm~2·时,其增益系数为1.7×10~(-2)/cm。研究了增益系数随热中子通量的变化关系,讨论了温度对增益的影响。实验表明核泵浦~3He-Ne体系有可能实现激射。     

分子束外延砷化镓单晶薄膜

MBE GaAs单晶薄膜的载流子浓度(1.8-8)×10~(16)cm~(-3),室温迁移率 3000-5000cm~2/V.3最高达5466cm~2/V.s,相应的77K迁移率为1.59 ×10~4cm~2/V.s.对高杂质浓度的外延层进行了阴极荧光(4.2K) 和SIMS 测量分析.     

Pb(Sc1/2Ta1/2)O3铁电薄膜的制备及性能研究

用Pb(CH3COO)2·3H2O、Sc(CH3COO)3·xH2O和C10H25O 5Ta为原材料,乙二醇甲醚为溶剂,用改进的溶胶-凝胶(Sol-Gel)法在Pt/Ti/SO2/Si基片上成功地制备出ABO3钙钛矿型结构Pb(Sc1/2Ta1/2)O3(PST)铁电薄膜.该薄膜是研制铁电微型致冷器和非致冷热释电红外焦平面阵列的优选材料.对制备出的PST薄膜进行了介电、铁电和热释电性能测试.测试得到在1 kHz下PST薄膜的介电常数为570,介电损耗为0.02.铁电性能良好,剩余板化强度为3.8～6.0 μC·cm-2,矫顽场为40～45 kV·cm-1.热释电系数为4.0×10-4～20×10-4Cm-2K-1.     

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.     

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.     

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.     

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.     

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.     

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.     

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