ZnSe/ZnS平板波导全光调制和电光调制特性

在室温,随着增加入射光强,我们首次在ZnSe/ZnS平板被导中观测到由于“带填充”效应而引起的全光调制和由于施加电场而引起的电光调制特性.     

基于调制偏振光的空间正交方位信息传递系统

介绍了一种基于调制偏振光的空间正交方位信息传递系统。系统利用调制和解调传递一个正交方位,用电光晶体对偏振光进行调制,电光晶体的感生主轴方向构成发射部分的基准方位。接收部分利用Wollaston棱镜和光电转换器进行解调,由感生主轴构成的基准方位和Wollaston棱镜的两正交光轴之间的夹角信息反映了正交方位传递的精确性。     

Chaotic frictional vibrations excited by a quasiperiodic load

A Duffing oscillator frictionally interacting with a moving belt under a quasiperiodic load is studied. The multiple-scales method is used to derive a system of two nonautonomous equations with small parameters, which describes the modulation of vibrations. It is shown that the system of modulation equations has a heteroclinic structure. Melnikov functions are used to analyze the domain of heteroclinic chaos __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 9, pp. 127–133, September 2006.     

Terahertz laser velocity modulation spectroscopy of ions

Velocity modulation spectroscopy has been investigated in the terahertz region, employing pure rotational transitions of ArH⁺ and rotation-tunneling transitions of H₃O⁺ to study the competition between pressure broadening and Doppler broadening on the lineshapes, neutral suppression, and modulation efficiency. Velocity modulation is demonstrated to be effective to frequencies as low as 60 cm⁻¹, yielding S/N values for ArH⁺ (770/1) that surpass published terahertz FM results by an order of magnitude.     

Experimental study of NRZ format wavelength conversion using electroabsorption modulator

In this paper, NRZ format wavelength conversion using cross absorption modulation (XAM) in InGaAsP MQW electroabsorption modulator (EAM) is investigated experimentally in detail for the first time, to the best of our knowledge. The influence of two key operating parameters, input signal power and bias voltage of EAM, on wavelength conversion performance is studied. Experimental results indicate that there exists optimal bias voltage for fixed input signal power and that there exists also optimal input signal power for fixed bias voltage and the lowest power penalty of 0.9 dB is obtained by optimizing these two parameters. The physical explanations are given for these results based on operating characteristic of EAM device. Finally, the probe light wavelength dependence of wavelength conversion is studied for span of 1530–1560 nm.     

有质动力和静电分离场对激光等离子体流体力学状态的影响

利用建立在欧拉坐标系上的一维电子_离子双流双温流体力学程序, 模拟了超短脉冲强激光 (1×1015W/cm2, 150fs)与线性密度梯度等离子体相互作用的流体力学过程. 模拟结果显示，入射激光与临界密度面的反射光叠加，在临界密度以下区域形成局域驻波， 产生的强有质动力在低密区驱动电子形成周期性密度结构——Bragg光栅，激光的反射被增 强. 临界密度处有质动力将等离子体分成向内和向外运动的两部分. 由于离子所受的有质动 力和热压强的梯度力远小于电子，体系产生了强静电分离场，离子的运动主要由该静电分离 场决定. 对双流双温模型和单流双温模型的模拟结果进行了比较. 当有质动力和热压强梯度 力较大时，两种模型对等离子体流体力学状态的描述有明显差异，单流双温模型无法描述此 时的流体力学状态. 关键词： 有质动力 密度调制 双流双温流体力学模型 单流模型     

Magnetic Field Modulated Direct Overwrite with Continuous Wave LaserIrradiation for Magnetic-optic Disks

1.IntroductionAtpresent,therearetwokindsofpracticalrewritableopticalstorage:phase-changeoptiCalandmagneto-opticalstoraged].Magneto-opticaldatastorageisattractiveformassdatastoragebecauseofitshighrecordingdensityandthecontinuouslyincreasingdatatransferrate.DirectoverwriteisapromisingschemetoobtainhighdatatransferratellJ.Magneticfieldmodulation(MFM)andlightintensitymodulation(Lin)arethemajormethodstorealizemagneto--opticaldirectoverwrite[2-8].InLIM,pulsedlaserintensityismodulatedaccordingtot…     

Microwave Reflectometry on HL-2A Tokamak

One of the most important electron density diagnostics, microwave reflectometry, has been developed on many large and medium nuclear fusion devices in recent years . Not only the electron density profiles with high temporal and spatial resolutions, but also the profiles of plasma rotation and turbulence can be obtained with this diagnostic system.     

Manifestations of Phase Transitions and the Thermooptical-Memory Effect in the Absorption Spectra of (N(CH<Subscript>3</Subscript>)<Subscript>4</Subscript>)<Subscript>2</Subscript>CuCl<Subscript>4</Subscript> Crystals

The manifestations of phase transitions and the spatial modulation of the structure of the (N(CH₃)₄)₂CuCl₄ crystal in its absorption spectra have been investigated. It has been established that the thermooptical-memory effect manifesting itself in the absorption spectra of this crystal entirely corresponds to the model of ordering of defects and impurities in a sample with a modulated structure. It is shown that, as a result of stabilization of the crystal studied in the incommensurate phase, its symmetry and the symmetry of the metal-halogen complex in it lower depending on the defect wave. This manifests itself as a marked shift of the intraionic-absorption bands and an increase in their intensity. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 386–390, May–June, 2005.     

基于相位编码的畸变不变联合变换相关器的设计

采用综合鉴别函数(SDF)的方法合成几个子参考图象,用于解决畸变不变识别问题.通过相位编码技术和对联合功率谱的振幅调制,缩小了零级相关峰的宽度,锐化了相关峰,消除了多目标输入时各目标图象之间的互相关项和参考图象及各目标图象之间的共轭相关项,增强了对目标定位和识别的能力,最后给出计算机模拟结果.