高能量LD泵浦Nd∶YAG板条激光器

为了获得高能量532 nm激光输出,利用电光调Q晶体LN,通过调Q同步驱动技术和LD侧面泵浦板条技术,获得高能量窄脉宽1.06 μm激光输出,泵浦非线性晶体KTP进行频率变换,实现高能量532 nm激光输出。在电源输入电流120 A、调Q驱动频率10 Hz的条件下,获得264 mJ的1.06 μm激光。利用该1.06 μm激光泵浦KTP获得最高能量为185 mJ的532 nm 绿光激光输出,1.06 μm到532 nm的转化效率为70%。实验结果表明:通过电光调Q技术和LD侧面泵浦技术,可以实现高能量窄脉宽1.06 μm激光输出,泵浦KTP可获得高能量绿光激光输出。     

LD泵浦双棒Nd:GdVO4激光器

为了获得可对红外成像探测器具有干扰效果的高功率、高重复频率3.8μm中红外激光,首先通过LD侧面泵浦双棒技术和高重复频率声光调Q技术,获得高功率高重复频率1.06μm激光,再将其作为泵浦光进行非线性差频试验,获得3.8μm激光输出。将输出的3.8μm中红外激光用于红外探测器的干扰试验,获得了较好的干扰效果。     

脉冲LD泵浦千赫兹1.57 μm全固态激光器

采用非稳腔光参量振荡（OPO）研制了千赫兹重复频率人眼安全波段全固态激光器。激光器采用电光调Q方式、脉冲激光二极管（LD）侧面泵浦Nd:YAG激光晶体实现了高光束质量的1.064m基频激光。光参量振荡部分采用Ⅱ类非临界相位匹配KTP晶体,为了获得较好的光束质量,OPO谐振腔采用平凸非稳定谐振腔结构,实现了千赫兹重频、窄脉冲1.57m波段激光输出。在脉冲激光二极管泵浦电流为125 A、电光调Q重复频率为1 kHz时,1.57m激光输出最大平均功率达到了4.67 W,激光脉冲宽度为4.3 ns,功率不稳定度为3%,激光泵浦阈值约为45 A。     

LD泵浦双棒Nd∶GdVO4激光器

为了获得可对红外成像探测器具有干扰效果的高功率、高重复频率3.8 μm中红外激光,首先通过LD侧面泵浦双棒技术和高重复频率声光调Q技术,获得高功率高重复频率1.06 μm激光,再将其作为泵浦光进行非线性差频试验,获得3.8 μm激光输出.将输出的3.8 μm中红外激光用于红外探测器的干扰试验,获得了较好的干扰效果.     

机载远程探测用高能量双波长激光器研究

激光器是机载远程光电探测系统的重要组成部分,其性能直接决定系统应用效果.首先从激光测距方程出发,分析不同探测体制以及双波长探测需求;然后针对半导体泵浦固体激光器进行研究,并对不同双波长实现方式进行了分析;最后通过试验验证,实现了高能量双波长激光输出.试验结果表明:通过主动电光调Q技术和LD侧面泵浦共腔谐振技术,可以实现高重频窄脉宽1.064μm和1.57μm双波长激光输出.     

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。     

高重频人眼安全光参变振荡器实验研究

介绍了连续激光二极管抽运声光Q开关Nd:YAG激光器抽运的高重复频率1.57μm人眼安全光参变振荡器实验研究结果.采用连续激光二极管三侧面抽运Nd:YAG模块和QSGSU-6型小型声光Q开关,1.57μm光参变振荡谐振腔置于1.06μm Nd:YAG激光谐振腔内,非线性晶体为X切割的KTP晶体,利用Ⅱ类非临界相位匹配光参变振荡输出1.57μm波长激光.在重频1kHz~5 kHz时进行了初步实验,在重频3kHz时,获得1.57μm高重复频率激光最大输出功率480mW,最大峰值功率58.8kW,脉宽2.72ns,电光效率达2.6‰.试验结果表明,连续激光二极管抽运声光Q开关内腔光参变振荡器是获得高频人眼安全激光的一种有效途径.     

光纤激光器泵浦光参量振荡器

为了获得小体积高功率3~5μm中红外激光输出,通过高重复频率驱动调Q技术和种子注入光放大技术,获得高功率高光束质量1.06μm光纤激光输出,外置起偏器获得两束激光输出,利用波片偏振旋光原理,实现两束偏振态一致的激光输出,泵浦非线性晶体PPLN进行频率变换,实现高功率3~5μm中红外激光输出。在电源输入电流60 A,调Q驱动频率50 kHz的条件下,获得最高功率6.2W的3.8μm中红外激光,1.06μm到3.8μm转化效率为16%。实验结果表明:通过光纤激光器泵浦光参量振荡器,可获得高功率3.8μm中红外激光输出。     

LD侧面泵浦Tm:YAG电光调Q激光的实验研究

介绍了一种激光二极管(LD)阵列侧面泵浦电光调Q的高峰值功率、窄脉宽的Tm:YAG激光器。使用LGS晶体作为电光Q开关,研究了白宝石堆片和格兰棱镜分别作为起偏器时激光输出的特性。研究表明:使用白宝石堆片作为起偏器时,随着泵浦能量的增加会有尾脉冲出现;而使用格兰棱镜作为起偏器时,则无尾脉冲。使用格兰棱镜作为起偏器时,该激光器输出激光中心波长为2.02μm,在重复频率为10 Hz时,可获得最大单脉冲输出能量为60 m J、脉冲宽度为65.6 ns、峰值功率为0.91 MW、斜效率为5.41%的激光输出。     

适于空间应用的高重复频率窄脉冲电光调Q激光器

给出了一种适用于空间应用的全固态高重复频率窄脉冲激光器。激光器采用超稳双porro棱镜直线谐振腔,以LD侧面抽运Nd…YAG板条,磷酸氧钛铷(RTP)晶体作为电光调Q开关,并利用偏振耦合输出激光。实现了激光脉冲重复频率为1kHz、平均功率为1.15W、脉冲宽度为1.3ns、光束质量因子M~2为M_x~2=1.20和M_y~2=1.23、波长为1064nm的脉冲激光输出。激光器结构紧凑,性能良好,可作为未来新型空间探测激光雷达系统的光源。     

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.     

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.     

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