飞秒染料激光放大器

本文用重复率为10Hz、调Q、Nd∶YAG激光器的二倍频输出泵浦四级染料放大器,把从对撞脉冲锁模(CPM)环形染料激光器中产生的43fs的光脉冲能量放大到100μJ,脉冲宽度为125fs,峰值功率为800MW,在用一组四棱镜系统对放大的光脉冲进行群速度色散补偿以后,得到了宽度为70fs的放大光脉冲输出,峰值功率达GW。     

一级放大的超短腔染料激光器

一、前言 超短腔染料激光器可产生窄脉冲、可调谐光脉冲输出。但由于其能量较小(～1μJ),它的应用受到限制。本文使用纵向泵浦的一级放大,可获得能量放大20倍左右,稳定性较好的ps激光脉冲,而且超短腔染料激光器光脉冲的时间抖动小,它可作为用于高时间分辨率研究中的探测光。     

XeCl中带宽限制的220 fs脉冲放大

稀有气体卤化物的受激辐射增益曲线带宽为200 cm-1,它允许放大亚皮秒脉宽的光脉冲。在早期的实验中，短脉冲准分子激光振荡放大系统的振荡源是采用准分子激光泵浦染料激光的倍频及放大技术。要将几台准分子激光器锁模，脉冲幵关之间维持高精度的同步是很复杂的。     

用脉冲激励激光产生微微秒光脉冲

脉冲激励产生的微微秒光脉冲的峰值功率,和连续激励时比较,具有很大的优点,对研究光和物质的相互作用极为重要。采用脉冲激励时,特别是对固体激光器,通常采用把放大介质和可饱和染料配合在一起,在Q开关的同时进行模同步的方法。超短光脉冲产生机理的实时处理法是精确而又方便的。利用脉冲激励来获得超短光脉冲时存在的最大问题是振荡的稳定性(重复性)。因此,本文介绍一下用可饱和染料产生稳定的微微秒光脉冲及得到脉宽可变的激光的     

超短行波放大自发辐射的研究

用泵浦能量具有梯度分布的横向同步泵浦方案,产生超短行波自发辐射光脉冲。以N_2激光为泵浦源,获得约50ps的染料光脉冲输出,以锁模Nd:YAG倍频光作泵浦源,获得8～15ps光脉冲。用条纹照相机和光学多道分析器测量了脉冲波形和光谱。 计算机模拟了行波放大自发辐射的瞬态行为,计算结果与实验结果相符合。     

染料放大器的ASE和飞秒脉冲放大

分析了染料放大器(DLA)的放大的自发辐射(ASE)的分布、上能级以及三重态粒子数分布。用数学方法模拟计算了泵浦作用时非饱和情形下染料分子的储能和飞秒脉冲的放大。我们认为,设计一个染料放大器必须考虑三重态积累对分子储能的影响。用调Q倍频Nd∶YAG脉冲同步泵浦染料二级放大器放大飞秒脉冲,得到的第一、二级放大倍数分别为1000和60,对于第一级放大,计算结果与实验结果基本相符。     

掺铒光纤放大器放大高速ps半导体激光脉冲的研究

理论与实验研究了掺银光纤放大器放大高速PS半导体激光脉冲的行为，给出了放大高速光脉冲时放大器的增益特性与光脉冲占空比之间的关系，占空比越大，输出光脉冲的峰值功率越小，理论与实验结果较好地一致。     

倍频连续波锁模Nd:YAG同步泵浦的亚微微秒脉冲的产生和放大

用倍频连续波锁模Nd:YAG激光器同步泵浦一若丹明6G染料激光器，可以得到稳定的、可调谐的亚微微秒脉冲。尽可能提高幅度和脉宽的稳定性，可以得到短于500毫微微秒的染料激光脉冲。与现有的同步泵浦染料激光器相比，这一新泵浦源的主要优点是特别适合于短脉冲的放大。采用这一技术，放大倍数高达2×106。     

超短光脉冲放大的研究

用激光锁模脉冲作激发源研究超快现象时,为了使光脉冲有足够高的峰功率,通过采用各种方法对超短光脉冲进行放大。为实现最佳光脉冲放大,本文对横向泵浦放大的放大自发辐射(ASE)的光谱特性,以及增益对泵浦区几何参数的依赖关系作了详细研究,在实验上获得放大的超短光脉冲。     

染料激光的偏振输出研究

用线偏振光把染料激光泵浦放大,若泵浦光的偏振方向x与染料的单向偶矩分布之起始对称轴一致,理论上表明,只输出偏振x为方向的激光,对各向同性偶矩分布,由于泵浦光和放大光在染料中传播时,其偏振方向均会旋转,故输出光的偏振度大减。我们主要用准分子和N_2激光泵浦染料激光放大,用起偏装置置入两个放大级之间,使之诱导末     

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