高重复频率大能量单纵模主振荡激光器

研制了一台高重复频率电光调Q单纵模主振荡激光器。利用高速电子电路负反馈控制系统,在激光器谐振腔内引入一个随光强动态变化的损耗,建立了准连续的预激光状态,在此基础上进行电光调Q,加上谐振反射器的纵模选择作用,最终实现了稳定的单纵模输出。激光重复频率为1kHz,脉冲宽度为15ns,最高脉冲能量为2mJ,在30min时间内,单纵模几率达100%。激光器结构紧凑,系统简单可靠,已成功应用于激光振荡-放大系统的振荡器中。     

千赫兹二极管抽运Nd∶YAG激光器

报道了一种采用双二极管抽运头、电光调Q实现高重频、窄脉宽Nd∶YAG激光输出特性。在重复频率1 kHz,二极管驱动电流65 A,BBO晶体电光调Q条件下,实现了平均功率6.5 W,电光效率10%,脉冲宽度17.25 ns的TEM00模1064 nm激光输出。研究了KD*P及BBO晶体的高重频工作特性,为下一步在高重复频率抽运时获得大能量的高光束质量激光输出奠定较好的基础。     

灯抽运单纵模种子源

在灯抽运Nd∶YAG激光器的基础上 ,提出一种新颖的在激光工作物质荧光辐射后沿控制KD P电光晶体调Q选单纵模的方法。在频率为 40Hz时获得单纵模几率为 10 0 %,输出能量为mJ量级 ,脉宽约为 18ns的稳定单纵模激光脉冲。用作MOPA系统的种子源 ,获得高效大能量输出的好结果。     

高重频Nd:YVO4声光调Q与RTP电光调Q激光器实验对比分析

报道了相同实验条件下激光二极管端面抽运生长型复合Nd:YVO4晶体声光调Q和RTP电光调Q激光器。应用声光调Q和RTP电光调Q分别实现了最高重复频率200 kHz和500 kHz的TEM00模1 064 nm激光输出,输出平均功率分别达到12.13 W和13.56 W,脉冲宽度分别为16.65 ns和27.27 ns,并首次对比了两种调Q体制下的高重频激光输出特性。实验结果表明,RTP电光调Q具有更好的高重频关断能力,但由于受到高压驱动的限制,RTP电光调Q无法在更高重复频率下实现窄脉宽高峰值功率激光输出,而在更高重频下仍有较好输出性能的声光调Q将取代电光调Q成为几百千甚至上兆Hz高重频激光器的首选调Q机制。     

914 nm LD泵浦RTP电光调Q的高效率Nd:YVO4激光器

报道了一种激光二极管（LD）端面连续抽运的高重频、高光光效率电光调Q Nd:YVO4激光器。采用RbTiOPO4（RTP）晶体对作为调Q元件,通过减小热效应和模式匹配技术,实现了高效率的高重频窄脉宽1 064 nm脉冲激光输出。一方面采用低吸收系数的914 nm波长抽运Nd:YVO4晶体,使晶体内热分布均匀,从而获得高量子效率的同时减小了热效应影响。另一方面通过优化泵浦光斑半径,实现泵浦光和振荡光好的模式匹配。在重频200 kHz时,获得了最高输出功率16 W,脉宽9 ns,单脉冲能量80 J,光束质量M21.2的稳定脉冲激光,泵浦吸收功率31 W,对应的光光转化效率为51.6%。据笔者所知,这是RTP电光调Q实现的最高效率的脉冲激光器。     

1.3414μm Nd:YAlO3电光Q开关脉冲激光器

本文介绍了一种用LiNb％晶体作为电光Q开关晶体的闪光灯泵浦1．3414μm Nd：YAlO3,电光调Q脉冲激光器,实验得到了脉宽45ns、输出能量312mJ的巨脉冲激光输出。     

高重复频率电光调Q全固态激光器研究进展

高重复频率窄脉宽全固态激光器在激光加工领域以及空间激光通信、激光雷达、激光测距等空间应用领域都具有巨大的市场需求和广阔的应用前景.利用电光调Q方式可以获得窄脉宽、大能量激光脉冲输出,且具有良好的稳定性.近年来,随着新型电光晶体的出现,电光调Q开关的工作重复频率得到了显著的提高.主要综述高重复频率电光调Q全固态激光器在高速Q开关性能及激光输出方面的研究进展,并简要报道了研究小组在该研究领域取得的最新实验结果.     

Nd^3＋：YAG固体激光器电光调Q激光脉冲的时域分析

Nd^3＋：YAG固体激光器多元激光精密同步合成技术是实现大能量、高峰值功率脉冲激光输出的重要途径。其关键技术是对Nd^3＋：YAG固体激光器电光调Q进行精密光电控制。通过对Nd^3＋：YAG固体激光器电光调Q理论分析和仿真，得到单元激光器不同控制参数下的输出特性，经电光调Q专题试验验证，脉冲激光输出波形与仿真结果相吻合，达到预期效果。在此基础上提出了激光精密同步合成的技术条件和可行性。     

大能量电光调Q脉冲序列输出全固态Nd∶YAG激光器

设计了激光二极管侧面泵浦两级放大电光调Q全固态Nd∶YAG激光器,实现间距可调的脉冲序列激光输出。使用U型封装的LD模块对晶体棒进行侧面泵浦,磷酸钛氧铷(RTP)晶体作为调Q晶体,通过提供调Q高压序列,获得了单个脉冲能量大于550 mJ,脉冲宽度小于8 ns,脉冲间隔180~240 μs可调的脉冲序列输出,脉冲序列间隔稳定,能量保持一致,激光器重复频率5 Hz。     

双支路电光Q开关高重频激光器研究

报道了一种采用LD侧面泵浦、双支路电光Q开关实现热退偏补偿的高重频固体激光器。在重复频率1 kHz时,实现了平均功率6.7 W,脉冲宽度16.7 ns的TEM00模激光输出,对千赫兹高重频、窄脉宽、高光束质量激光器的研发具有一定的参考价值。     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

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.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.