2012 Vol. 24, No. 06

Recommend Articles
2012, 24.
Narrow linewidth all-fiber laser with 666 W power output
Wang Xiaolin, Zhou Pu, Xiao Hu, Su Rongtao, Guo Shaofeng, Si Lei, Xu Xiaojun, Liu Zejin
2012, 24: 1261-1262. doi: 10.3788/HPLPB20122406.1261
Abstract:
A master oscillator power amplifier (MOPA) structured narrow-linewidth Yb-doped fiber laser is set up in all-fiber format. In the system, a single frequency laser is broadened to be a 0.3 GHz-linewidth seed by using noise phase modulation technique. The power of the seed is then scaled from 10 mW up to 666 W through a four-stage power amplifier chain. Further power-scaling of this MOPA system can be expected since our experiment is only pump-power limited.
Repetition rate pulsed power technology and its applications: (iii) The role of magnetic switches
Jiang Weihua
2012, 24: 1269-1275. doi: 10.3788/HPLPB20122406.1269
Abstract:
Starting from the basic characteristics of magnetic materials, this paper explains the operation principle of the magnetic switch and, by using simple experiments, demonstrates its effectiveness in pulsed power generation. Typical usages of the magnetic switch are described, such as pulse compression, magnetic assistance, and saturable transformer. Finally, three types of application circuits are introduced, including pulsed laser driver circuit, high-power accelerator driver circuit, and semiconductor opening switch(SOS) driver circuit.
Study on process of marking two-dimensional codes on air circuit breakers by UV laser
Wu YuWen, Guo Liang, Zhang Qingmao, Lü Qitao, Zhang Chao
2012, 24: 1329-1334. doi: 10.3788/HPLPB20122406.1329
Abstract:
The quality of two-dimensional codes on air circuit breakers depends on laser parameters such as scanning speed, Q frequency, line spacing, electric current and defocusing distance. The experiment changed laser parameters according to the orthogonal table L16(45). Color difference was measured by a spectrophotometer and code success ratio was tested by a bar code scanner. Orthogonal analysis and range analysis were carried out to study the influence of laser parameters on marking effect. The experiment shows that, there is a threshold color difference and the linear relationship between color difference and code success ratio is good. Perfect two-dimensional codes are obtained with optimum laser parameters, which are 1 000 mm/s scanning speed, 20-30 kHz Q frequency, 0.04 mm line spacing, 28 A electric current and -1 mm defocusing distance.
High-precision tracking and pointing control technique
Xiong Zhenkai, Chen Tingfeng
2012, 24: 1339-1343. doi: 10.3788/HPLPB20122406.1339
Abstract:
For the multifunctional demand of target tracking and pointing, the paper designs a tracking and pointing controller by combining the ideas of least standard deviation estimation and tracking control. The design realizes the fusion of target position forecasting and servo control, and optimizes the system structure. The improved Kalman filter based on current statistical model forecasts the parameters of target state. The solution control based on adaptive sliding mode resolves the problem of servo system position control. The simulation results show that this controller works stably with strong anti-jamming ability and high tracking and pointing precision.
Controlled bonnet polishing system for large aspheric lenses
Pan Ri, Yang Wei, Wang Zhenzhong, Guo Yinbiao, Wang Jian, Zhong Bo
2012, 24: 1344-1348. doi: 10.3788/HPLPB20122406.1344
Abstract:
The paper presents the design and manufacture of controlled bonnet polishing system used for large aspheric lenses polishing. Kinematics simulations of the designed structure show that, the workspace of the spin axis of bonnet tool can meet the requirement of large aspheric lenses polishing with continuous precession processing. A polishing experiment on the circular flat workpiece with a radius of 320 mm has been carried out. The profile accuracy of the workpiece is fine after 24-hour polishing. The surface roughness reduces from 0.272 to 0.068, and the peak-to-valley value reduces from 1.671 to 0.905. The results of the experiment show that the controlled bonnet polishing system is featured with high precision and high stability, meeting the design requirements, and the system can improve the profile accuracy of workpieces effectively.
Data processing of scintillation index measurement in real atmosphere
li Fei, Wu Yi, Hou Zaihong
2012, 24: 1349-1352. doi: 10.3788/HPLPB20122406.1349
Abstract:
Considering system background noise, detector inherent noise and shot noise, the mathematical model of scintillation index measurement system was amended and the current method for data processing was modified. An experiment of laser propagation was carried out at the range of 1 km, and the experimental data were processed with the original and the modified methods. The results show that the amended model is more consistent with experimental data than the original one; shot noise is one order of magnitude larger than system background noise and it influences the accuracy of measurement seriously; the fluctuation of signal-to-noise ratio(SNR) has less influence on the modified method than on the original method; and the accuracy of the modified method is higher than the original one in low-SNR condition.
Tight focusing properties of double-ring-shaped azimuthally polarized beam through annular high numerical aperture
Liu Xiaoyun, Tian Bo
2012, 24: 1365-1368. doi: 10.3788/HPLPB20122406.1365
Abstract:
By using the Richards-Wolf vector diffraction theory, the focusing properties of a double-ring-shaped azimuthally polarized beam through an annular lens with high numerical aperture are studied. Expressions of intensity distribution on the focal field are derived. Numerical calculations are performed to compare the influence of the beam and lens parameters on the tight focusing properties. It is shown that sub-wavelength focal spots of wide applications can be obtained on the focal plane, and correlated parameters of the incident beam and the numerical-aperture of the lens do affect the focusing. Moreover, longer depth of focus (nearly 28 times the incident wavelength) can be generated with a lens of higher numerical aperture.
Laser coverage on defect in laser conditioning process
Dai Fu, Yang Liming
2012, 24: 1385-1390. doi: 10.3788/HPLPB20122406.1385
Abstract:
The laser energy covering the defect in laser-conditioning process is studied, and its characteristics in different laser-conditioning processes are analyzed. Theoretical analysis shows that, with the same conditioning efficiency, the laser energy coverage rate of single-step conditioning is better than that of multi-step conditioning. From laser-conditioning experiments of the HfO2/SiO2 high reflective coating deposited by E-beam evaporation, we know that the LIDT (laser-induced damage threshold) enhancement of the coating after single-step conditioning is better than that of the coating after multi-step conditioning with the same conditioning efficiency. Using the highest irradiating energy of 112% E0, the LIDT of coating after 5-step conditioning is 183.5% of that before conditioning.
Surface topography of parallel grinding process for nonaxisymmetric aspheric lens
Zhang Ningning, Wang ZhenZhong, Pan Ri, Wang Chunjin, Guo Yinbiao
2012, 24: 1391-1395. doi: 10.3788/HPLPB20122406.1391
Abstract:
Workpiece surface profile, texture and roughness can be predicted by modeling the topography of wheel surface and modeling kinematics of grinding process, which compose an important part of precision grinding process theory. Parallel grinding technology is an important method for nonaxisymmetric aspheric lens machining, but there is few report on relevant simulation. In this paper, a simulation method based on parallel grinding for precision machining of aspheric lens is proposed. The method combines modeling the random surface of wheel and modeling the single grain track based on arc wheel contact points. Then, a mathematical algorithm for surface topography is proposed and applied in conditions of different machining parameters. The consistence between the results of simulation and test proves that the algorithm is correct and efficient.
Fourth harmonic generation of DKDP crystal
Ji Shaohua, Zhang ShaoJun, Xu Mingxia, Liu Bao’an, Zhu Lili, Zhang Lisong, Xu Xinguang, Wang Zhengping, Sun Xun
2012, 24: 1406-1408. doi: 10.3788/HPLPB20122406.1406
Abstract:
Deuterated dihydrogen phosphate(DKDP) crystals of different deuterium contents were cut for type-I non-critical phase-matching with the direction at 90 to the crystal z axis and at 45 to the crystal x axis, and then measured in the fourth harmonic generation experiments with fundamental wavelengths of 1 064 nm and 1 053 nm, respectively. The optimum deuterium content of DKDP crystal was confirmed by measuring the relation between deuterium content and phase-matching angle. The results indicate that DKDP crystal can not achieve non-critical phase matching by adjusting its deuterium content at room temperature with the fundamental wavelength of 1 064 nm. However, at the fundamental wavelength of 1 053 nm, the optimum deuterium content of DKDP crystal is 85%, to achieve non-critical phase matching at room temperature.
Design of built-in tapered waveguide of 95 GHz TE03 gyrotron
Xue Changjiang, Pan Wenwu, Chen Shitao
2012, 24: 1434-1438. doi: 10.3788/HPLPB20122406.1434
Abstract:
The design method of high-order tapered waveguides is presented according to the mode coupling theory, and the built-in, TE03 mode, modified Dolph-Chebychev tapered waveguide of 95 GHz gyrotron is studied. Reliable optimal geometric parameters are obtained with a self-developed mathematical programme.The tapered waveguide of 95 GHz gyrotron designed is compact.Its parasitic-mode-suppression is 30 dB, which is verified by electromagnetic field simulation and meeting the design requirement.The burned pattern measured at output of the waveguide indicates good expected inner radius change of the gyrotron. The results show that the method can efficiently guide the design of high-order overmode tapered waveguide.
Design of reverberation chamber excited by short pulse
Li Shuang, Wang Jianguo, ,
2012, 24: 1439-1444. doi: 10.3788/HPLPB20122406.1439
Abstract:
According to the distributions of electromagnetic field in an ideal resonator, the parameters affecting the field distribution were summarized firstly. Then the model of reverberation chamber(RC)was designed according to accustomed rules and special standards to judge the field uniformity in this kind of RC were also established. Lastly the influences of the cavity shape and the method of source stirring on the characteristics of the electric fieldin the RC were analyzed. The standard deviation of electric field in the RC is reduced by 0.4 dB by moving the source continuously along ten positions. The numerical simulation shows that the usage of the complex resonator is effective to improve the homogeneity of the field and validates the feasibility of moving the source continuously in the RC excited by short pulse to improve the field uniformity.
On-line optimization of isochronous field of separated-sector cyclotron
Zeng Xianqiang, , Jing Lan, Yao Ze’en, Hao Huanfeng, Gou ShiZhe
2012, 24: 1458-1460. doi: 10.3788/HPLPB20122406.1458
Abstract:
This paper introduces the design and optimization of the isochronous field of separated-sector cyclotron (SSC) in the cooling storage ring of the Heavy Ion Accelerator in Lanzhou (HIRFL-CSR). Based on the HIRFL-CSR main Oracle database system, the main interface of the control system is designed. Through this interface, the values of power supply current can be given and read, and the beam phase information can be updated in real time. The isochronous magnetic field model is established by Kb-Kr and Lagrange methods, and the field is optimized on the basis of the actual phase measurement. The optimization of the isochronous field improves the beam quality by effective control of the drift of beam phase.
Matlab simulation on femtosecond laser spectrum division in optical A/D converters
Wang Bo, Sun Shengnan, Tao Shixing, Li Zeren
2012, 24: 1507-1512. doi: 10.3788/HPLPB20122406.1507
Abstract:
A 120 GS/s optical sampling clock in A/D converter is introduced, and the method of generating such a sampling clock and an optical oscilloscope based on the sampling clock are demonstrated. Matlab simulation is used to realize the division and multiplexing of femtosecond lasers spectrum, and the problems in using the generated optical sequence to sample are discussed. The simulation result of Matlab is compared with that of Optisystem, and finally the attenuation rate of the optical sampling sequence calculated by Matlab is used to optimize the sequence simulated by Optisystem.
综述
快脉冲直线变压器气体开关技术
Cong Peitian, Qiu AiCi
2012, 24: 1263-1268. doi: 10.3788/HPLPB20122406.1263
Abstract:

阐述了Z箍缩驱动惯性聚变装置对快脉冲直线变压器气体开关的需求背景,介绍了快脉冲直线变压器气体开关技术发展的基本要求及国际研究进展,归纳了近年来主要研究成果和对当前研究有重要借鉴意义的结论,给出了提高静态稳定性、降低触发阈值和延长开关寿命的措施。介绍了气体放电的汤逊和流注理论,指出:在不大于1.5106 Pacm范围内,汤逊理论完全适用于描述气体开关自击穿过程。根据巴申定律、Meek击穿判据,给出了开关气压和间距设计要点,分析了多间隙开关间隙数量和间隙的电压分布均匀性对开关自击穿电压的影响。根据触发击穿延时经验公式,归纳了降低触发电压阈值的技术途径。介绍了1维的电极熔蚀判据,并总结了减轻电极烧蚀的方法和措施最后指出开关技术研究总体策略和方法。

高功率激光与光学
SiO2/HfO2高反射膜的研制
Cheng Xinbin, Shen Zhengxiang, Jiao Hongfei, Ma Bin, Zhang Jinlong, Ding Tao, Wang Zhanshan
2012, 24: 1276-1280. doi: 10.3788/HPLPB20122406.1276
Abstract:

主要讨论了电子束蒸发SiO2/HfO2薄膜的面形控制和损伤性能。研究了电子束蒸发工艺参数对薄膜应力以及面形的影响;分析了制备工艺对薄膜吸收、节瘤缺陷密度的影响,测量了制备薄膜的损伤阈值。研究结果表明:调整SiO2蒸发时的氧分压可以有效地将薄膜的应力控制在-250~-50 MPa。同时采用金属Hf蒸发可以显著地将节瘤缺陷密度从12.6 mm-2降低至2.7 mm-2,同时将损伤阈值从30 J/cm2提高至55 J/cm2。

自适应光学系统变形镜控制电压预测
Shi Xiaoyu, Feng Yong, Chen Ying, Tan Zhiying, Li Xinyang
2012, 24: 1281-1286. doi: 10.3788/HPLPB20122406.1281
Abstract:

在校正大气湍流畸变波前相差的自适应光学系统中,利用基于Levenberg-Marquardt学习算法的非线性反向传播神经网络技术(LMBP)对变形镜控制电压进行预测。以对受横向风影响的大气湍流畸变波前斜率数据为研究对象,通过数值仿真方法,研究了基于LMBP算法的自适应光学系统变形镜电压非线性预测控制算法。通过实验发现,预测电压和变形镜实际控制电压拟合效果良好。讨论了回溯帧数对预测效果的影响,并与基于递推最小二乘(RLS)算法的线性预测算法进行比较。对比结果表明,基于LMBP算法的非线性电压预测方法比基于递推最小二乘法的线性电压预测方法能更有效地降低系统由伺服延迟引起的误差。

高功率全光纤激光器特性
Zhang Hong, Yang Chunping, Li Wei, Dong Haiyan, Yang Chao, Wang Qi, Xiao Xiaoguo
2012, 24: 1287-1289. doi: 10.3788/HPLPB20122406.1287
Abstract:

介绍了采用国产光纤光栅研制的全光纤激光器,单端泵浦获得468 W的连续激光输出。从理论上分析了光纤光栅的反射率与波长的关系,计算了输出谱宽值,与实验测得的数据相符。全光纤激光器的光-光转换效率达到70%,且随着功率的增加,光纤光栅的中心波长有向长波方向漂移的趋势。在最高输出功率下180 s之内输出功率波动在0.04%以内。  

光纤激光相干合成高速高精度相位控制器
Su Rongtao, Zhou Pu, Wang Xiaolin, Han Kai, Xu Xiaojun
2012, 24: 1290-1294. doi: 10.3788/HPLPB20122406.1290
Abstract:

基于随机并行梯度下降算法(SPGD)和现场可编程逻辑阵列(FPGA)设计制作了相干合成(CBC)相位控制器。理论分析表明,该控制器单次迭代速率大于1.125 MHz,对于2路和16路相干合成,其平均控制带宽的理论值分别大于70 kHz和9 kHz,与现有的SPGD算法相位控制器相比有了量级上的提高。利用该控制器进行了验证性实验,表明该控制器能够实现高速高精度相位控制。当利用相位控制器对两路激光的相位进行锁定时,目标圆孔内能量提高了1.51倍,远场光斑对比度提高了5.29倍。

压电驱动器布置对光栅拼接误差的影响
Zhang Junwei, Chen Wei, Zhou Yi, Wang Xiao, Zhou Hai, Liu Pengwei, Huang Jinyong
2012, 24: 1295-1300. doi: 10.3788/HPLPB20122406.1295
Abstract:

分析了两种光栅拼接调整机构(三角形和L形),利用有限元分析软件对这两种光栅调整机构进行了模态分析和优化分析设计。相同光栅尺寸下(以口径为450 mm420 mm60 mm光栅为例),驱动器三角形分布的固有频率与L形分布的固有频率相差无几,一阶频率分别为58.816 Hz和58.864 Hz。对两种驱动器布置方式引入的误差进行了分析比较,计算结果表明:三角形调整机构的最大误差比L形的大,同时三角形分布控制算法较L形的复杂。在主动控制中三角形模型误差迭代次数多,不利于控制。因此L形的压电驱动器布置方式优于三角形。

等截面超-超引射器流场结构及引射性能
Chen Jian, Wang Zhenguo, Wu Jiping, Xu Wanwu
2012, 24: 1301-1305. doi: 10.3788/HPLPB20122406.1301
Abstract:

为考察超声速引射器直接引射超声速二次流时的性能,采用纹影技术和压力测量手段对一等截面超-超引射器的流场结构及其引射性能进行了实验研究。研究结果表明:一、二次流交汇后在混合室前段形成了复杂的超声速流场结构。根据二次流在混合室入口流动状态的不同,可将超-超引射划分为非饱和超-超引射和饱和超-超引射两种工作状态;二次流在混合室入口处产生的激波提高了引射器的压力匹配性能;在给定的引射系数下,引射器的增压性能随二次流马赫数的增大而降低,而引射马赫数对引射器压力恢复性能的影响不大。

中红外高能激光探测单元
Chen Shaowu, Zhang Jianmin, Yuwen Cuilei, Feng Gang
2012, 24: 1306-1310. doi: 10.3788/HPLPB20122406.1306
Abstract:

基于光电导探测原理,分析了影响室温光导型InSb探测器在中红外激光功率参数测量中的因素,得到了材料掺杂数密度、环境温度对探测器暗电阻、光谱响应率和光谱探测率的影响规律;开展了探测器在强激光辐照下的热效应理论模拟和实验研究,模拟分析了探测器在激光辐照下的动态响应特性。结果表明:针对测量系统中所使用的探测器,在激光功率密度小于4 W/cm2时,激光热效应对测量结果的影响可忽略;研制了相应的恒流源驱动电路,实现了中红外高能激光功率参数的探测。

H2+和H3+系统的电子频谱与高次谐波谱
Dai Chunyan, Yu Chuan, Zhang Guizhong, Xiang Wanghua, Yao Jianquan
2012, 24: 1311-1314. doi: 10.3788/HPLPB20122406.1311
Abstract:

针对单电子H2+和双电子H3+系统,采用对称分裂算符法求解波函数的时间演化。计算了电子的含时频谱和体系的高次谐波谱,结果表明:电子频谱和高次谐波谱呈互补规律,即电子频谱峰值出现在基波的偶数倍频率位置,高次谐波则出现在奇数位置。对高次谐波谱随软化库仑参数的变化规律进行了数值研究,发现只在软化库仑参数的一定范围内才产生高次谐波,对该现象作了解释。

无衍射贝塞尔光束非球面透镜设计
Zhang Qian’an, Wu Fengtie, Zheng Weitao
2012, 24: 1315-1318. doi: 10.3788/HPLPB20122406.1315
Abstract:

提出一种可产生无衍射贝塞尔光束的非球面透镜-贝塞尔透镜,该透镜由球面和非球面组成,呈旋转对称结构。利用光学设计软件ZEMAX通过光线追迹法对贝塞尔透镜进行设计,在设计和优化过程中,将出射光线与光轴的夹角作为边界条件,二次曲线参量和高次项系数作为变量。结果表明:利用标准二次曲线加上第一个高次项就可以得到比较理想的优化结果,设计的非球面贝塞尔透镜可以产生具有贝塞尔光束特性的无衍射光束。

基于主元分析的随机相移算法
Xu Jiancheng, Sun Lili
2012, 24: 1319-1323. doi: 10.3788/HPLPB20122406.1319
Abstract:

将统计理论中的主元分析应用到干涉条纹分析中,提出一种基于主元分析的随机相移算法。该算法先将多帧条纹数据分解成不相关的主元成分,然后从主元成分中提取2维相位信息。数值模拟结果表明:该算法不需要迭代运算就能从4帧完全随机相移干涉图中有效提取相位信息,运算时间少,精度高。实验结果表明主元分析相移算法比现有迭代相移算法更适合于随机相移干涉图分析。

反射式液晶空间光调制器电控光束偏转
Zhao Xiangjie, Zhang Dayong, Luo Yongquan
2012, 24: 1324-1328. doi: 10.3788/HPLPB20122406.1324
Abstract:

为获得较大的光束电控偏转范围,使用空间分辨力高达8 m的反射式液晶空间光调制器实现了对入射632 nm激光的电控偏转。利用双光束共焦干涉方法测量了液晶空间光调制器的电控相位延迟特性,最大相移量可达3。根据二元光学理论和器件的电控相位延迟特性,设计了周期台阶相位模式和相应的加载灰度图,以最大衍射效率实现对入射光束的闪耀电控偏转。结果表明:相位模式台阶数为8时,可以实现10 mrad的光束偏转,闪耀级次衍射效率可达46%。利用二元光学的衍射模型对影响衍射效率的关键因素进行了分析,认为器件较低的填充因子和周期台阶模式相位重置点诱导的指向矢回程区是限制光束衍射效率的主要因素。

高分辨力哈特曼传感器的快速波面重构和拼接
Yan Hong, Luo Zhongxiang, Ye Yidong, Xiang Rujian, Wang Feng, He Li
2012, 24: 1335-1338. doi: 10.3788/HPLPB20122406.1335
Abstract:

建立哈特曼传感器的模型,证明在高空间分辨力下,可以采用Hudgin模型进行波面重构,避免了采用Fried模型带来的复杂性。对哈特曼子孔径缺失破坏连续性的问题进行了分析,介绍了相应的边缘处理算法。完成了基于离散傅里叶变换的波面重构算法数值模拟,实现了波面的无损重构。针对实际应用中输入波面在被遮挡处不连续的问题,提出了基于最小二乘解的拼接方案,实现了非连续波面拼接。分析了影响波面重构速度的主要因素,提出了提高波面重构性能的方法。

基于固定校正镜的折衍共形光学系统设计
Shen Mande
2012, 24: 1353-1356. doi: 10.3788/HPLPB20122406.1353
Abstract:

设计了一个大扫描视场的折衍混合红外共形光学系统,共形成像系统工作波段为3.7~4.8 m,相对孔径为1/2,焦距为120 mm,扫描视场为40。由于共形光学系统具有大偏心、大倾斜光学特性,像差校正难度较大,设计中采用固定校正镜和折衍混合混合结构校正了共形光学元件的像差,引入了非球面和衍射面有效消除了各个扫描视场的像差。设计结果表明:光学系统光阑与探测器冷光阑重合,满足100%冷光阑效率。在40扫描视场范围内,共形光学系统的光学传递函数曲线接近衍射极限,成像良好。

高斯脉冲在半导体光放大器中传输的解析表征
He Wei, Hui ZHanqiang, Wu Huimin
2012, 24: 1357-1364. doi: 10.3788/HPLPB20122406.1357
Abstract:

采用解析方法,在考虑材料损耗和色散的情况下,详细研究了无啁啾高斯脉冲和啁啾高斯脉冲在半导体光放大器中传输的物理过程,分析了强度增益、脉冲宽度和频率啁啾与线宽增强因子、色散系数、小信号增益特征参数及初始啁啾之间的关系。结果表明:当输入变换极限的高斯脉冲时,色散会引起增益压缩,脉冲展宽和频率啁啾;同样情况下,线宽增强因子越大,脉宽加宽越明显,输出脉冲啁啾越大,且随着线宽增强因子的增大,输出脉冲啁啾极大值向特征参数值较小的一边移动。当输入啁啾高斯脉冲时,初始脉冲啁啾越大,增益压缩越明显,啁啾系数为正时,脉冲单纯展宽,输出啁啾随特征参数的增大而逐渐减小,啁啾系数为负时,初始啁啾与群速度色散导致的啁啾相互竞争,致使脉冲先被压缩后被展宽;脉冲最窄处对应的特征参数随线宽增强因子的增大而先增大后减小,输出啁啾随特征参数的增大而经历振荡后趋于平稳。

光纤放大器对短脉冲串动态响应的半解析
Duan Zhichun, Zhou Jifang, Chen Jianguo, Wang Fanhou, Gao Zenghui, Huang Yongping, Chen Haitao
2012, 24: 1369-1375. doi: 10.3788/HPLPB20122406.1369
Abstract:

针对脉冲周期在ms量级、脉宽为ns量级的高功率激光系统输出的短脉冲串,根据其周期性特征及放大过程的特点,在忽略损耗系数和自发辐射的情况下,将1个周期近似分为泵浦和放大2个阶段。运用端面泵浦瞬态速率方程组,导出了2阶段变换时刻所对应的上能级粒子数之间的半解析关系式。据此,在模拟光纤长度对增益影响的基础上,研究了2阶段腔内平均上能级粒子数密度随时间的周期性变化关系,定量分析了脉冲前沿消耗增益对脉冲后沿形状的影响。结果表明:光脉冲前沿增益可达29.22 dB,其后沿增益低至0.82 dB,光脉冲后沿波形必然存在畸变,验证了所得结论的合理性。

ICF与激光等离子体
六通道掠入射软X射线针孔照相技术
Li Jun, Duan Shuchao, Huang Xianbin, Li Jing, Zhou Shaotong, Zhang Siqun
2012, 24: 1376-1380. doi: 10.3788/HPLPB20122406.1376
Abstract:

在对平面反射镜高能X射线截止原理分析研究的基础上,为传统的针孔照相系统配置了光学滤片加平面反射镜组成的滤波系统,消除了大部分的高能尾部的影响。介绍了六通道掠入射软X射线针孔相机的结构设计、工作原理及性能。将光源按光子能量切割成6个能段分别进行记录,滤波后各通道的出射光为窄带软X射线。在阳加速器上对六通道掠入射软X射线针孔相机系统进行考核,加速器输出电流为779 kA,电流上升时间为75 ns,使用的负载为16根环形W丝阵,成功获取了6个通道的针孔照相图像,并结合Dante谱仪相应通道测得的功率时间谱进行了对比分析,确定了部分Z箍缩辐射热点的图像与功率发射谱的对应关系。

适用于放大自发辐射平滑光束的脉宽压缩方法
Xiang Yihuai, Tang Xiuzhang, S.szatmari, B.janos
2012, 24: 1381-1384. doi: 10.3788/HPLPB20122406.1381
Abstract:

为了增加靶上的功率密度和耦合效率,基于饱和增益开关原理,发展了一种适用于放大自发辐射平滑光束的脉宽压缩方法。利用该方法,在赛格德大学的一台放电泵浦KrF准分子激光器上进行了实验,将该激光器输出的脉宽为14.5 ns的放大自发辐射光束压缩到了7.5 ns,并且保持了光束原有的均匀性。

超短超强激光产生正电子的蒙特卡罗模拟
Yan Yonghong, Zhao Zongqing, Wu Yuchi, Gu Yuqiu, Cao Leifeng, Yao Ze’en, Teng Jian, Dong Kegong, Liu Dongxiao, Fan Wei, Wei Lai, Yu Jinqing
2012, 24: 1396-1400. doi: 10.3788/HPLPB20122406.1396
Abstract:

通过理论分析,建立了超短超强激光与固体靶作用产生正电子的蒙特卡罗模拟模型及Geant4模拟程序。模拟研究了靶材料、靶厚度及超热电子温度等对正电子产额的影响,结果表明:对铝、铜、锡、钽、金、铅6种靶材料,金靶的正电子产额最高,是优秀的正电子产生靶;不同超热电子温度下存在不同的最佳靶厚度,在最佳靶厚度以下,正电子产额随靶厚度增长而增大,靶厚度取3 mm较为合适;超热电子温度越高,正电子产额也越高,提高激光强度是增加正电子产额的有效途径。模拟研究给出了正电子角分布及其能谱,结果显示,正电子发射明显前倾,从大于90方向范围发射的正电子数量极少,且超热电子温度越高前倾特点越明显,能量呈类麦克斯韦分布,靶背法线方向出射的正电子的温度随超热电子温度升高而升高。

微流控制备单分散微米级SiO2微球
Gao Cunmei, Luo Xuan, FanG Yu, ZhanG QinGjun, Du Kai, TanG YonGjian
2012, 24: 1401-1405. doi: 10.3788/HPLPB20122406.1401
Abstract:

采用软模板法制备出了聚二甲基硅氧烷微流控装置。利用该装置讨论了正硅酸乙酯和氨水的用量分别对反应体系凝胶化时间的影响,确定了制备SiO2微球的优化反应体系,即二甲基乙酰胺、正硅酸乙酯和氨水的体积比为8∶4∶1,实验所需的反应温度为60 ℃。实验发现:在微流体通道中,分散相的流速越大,粒径越大;连续相流速越大,粒径越小。因此,通过控制微流控装置中分散相和连续相的流速制备了粒径40~220 m的单分散SiO2微球,并对其形貌进行表征。光学显微镜和粒径分析均表明所制备的SiO2微球球形度高,单分散性好。

射频感应等离子体制备球形钛粉的成分分析
Gu ZhonGtao, Ye GaoyinG, Jin YupinG
2012, 24: 1409-1413. doi: 10.3788/HPLPB20122406.1409
Abstract:

射频等离子体制备球形钛粉技术是利用等离子体炬产生的高温热将形状不规则的钛粉快速熔融成液滴,随后急冷,冻结成球形钛粉。通过射频等离子体球化处理前后的钛粉的粒度与粒径分布的测试表明,钛粉经过球化处理后,平均粒度基本上没有改变,而粒径分布相对变窄。实验通过随机对球化处理的钛粉进行X射线衍射谱检测,发现最终获得的球形钛粉没有物质结构和相的变化。C,O,H和N的含量有所降低,而Ti的含量略有所增加,可见射频等离子体的球化处理有一定的纯化作用。

熔石英表面损伤修复点的损伤概率
Jiang Yong, Yuan Xiaodong, Liu Chunming, He Shaobo, Luo Chengsi, Wang HaiJun, Lv Haibing, Zheng Wanguo, Xiang Xia, Zu Xiaotao
2012, 24: 1414-1418. doi: 10.3788/HPLPB20122406.1414
Abstract:

针对3个光斑尺寸的CO2激光辐照尺寸小于400 m损伤点后得到的修复点,从4个方面对损伤修复点经355 nm激光辐照后的损伤概率分别进行研究。结果表明,根据修复光斑尺寸或损伤点尺寸分别讨论修复点的损伤概率,更能反映修复点的抗激光损伤能力。通过分别讨论可以看出,采用小光斑CO2激光辐照损伤点或者修复尺寸小于200 m的损伤点,修复成功率超过90%。同时,可以通过损伤修复点的激光损伤阈值都服从正态分布的规律来预测修复点的损伤概率。

飞秒激光渡越辐射时间特性的实验研究
Wang Guangchang, Ma Chunsheng, Zhang JianWei, Bai Chunyan, Liu Yuhong, Zheng Zhijian
2012, 24: 1419-1423. doi: 10.3788/HPLPB20122406.1419
Abstract:

为了探索渡越辐射(TR)的时间特性,在100 TW掺钛蓝宝石飞秒激光器上利用光学条纹相机,在靶背表面法线方向测量了TR时间分辨成像光斑。实验测量结果显示:TR时间分辨成像光斑呈长条状,而辐射区域有发散角、有光强分布。 TR信号强而快,持续时间短,为ps量级,最先到达屏幕上。其他成分光辐射信号弱而慢,持续时间长,为ns量级,最后到达屏幕上。TR的时间特性能为鉴别和判断TR信号提供了新的依据。

量纲分析法求解辐射热传导自相似解
Zhang Lu, Yan Ji, Yang Jiamin, Ding Yongkun
2012, 24: 1424-1428. doi: 10.3788/HPLPB20122406.1424
Abstract:

通过量纲分析,将辐射流体方程简化为一阶常微分方程组的形式,进而结合数值计算求得热波烧蚀自相似解。流体方程涉及的内能、状态方程表达式采用依赖于温度、密度两个参量的形式,且参数可调,适用性较广。源边界条件可为恒温、恒流、恒压、常密等情况。以恒温源为例,给出了X射线加热Au壁时烧蚀质量与烧蚀压的定标关系,与文献结果及MULTI辐射流体程序计算结果吻合较好。

平面调制靶的正弦波曲面超精密加工与表征
Huang YanHua, Gao DangzHong, Xie Jun, Tong WeicHao, Yuan GuangHui, Ma Xiaojun
2012, 24: 1429-1433. doi: 10.3788/HPLPB20122406.1429
Abstract:

采用超精密车削技术加工微尺度正弦波调制曲面微结构,解决了尖刃金刚石刀具刃磨和刀具对中等关键技术,研究了进给量、背吃刀量和主轴转速等主要切削参数对铜模板表面粗糙度的影响规律。加工出波长为(20~150)m0.5 m﹑峰谷高度差为(0.2~20)m0.1 m的带正弦波调制曲面。采用原子力显微镜对模板表面轮廓扫描,在20 m20 m的范围内,其表面粗糙度均方根值小于10 nm。将正弦波调制曲面测量结果与理论轮廓进行比较,采用最小二乘寻优算法评定轮廓误差。完成了曲面轮廓的功率谱表征,利用加工的曲面微结构制备了平面调制靶,实现正弦波调制曲面轮廓的精确转移。

加速器技术
轴对称静电场的束流光学模拟与设计
Ke Jianlin, Wu Chunlei, Zhou Changgeng
2012, 24: 1445-1448. doi: 10.3788/HPLPB20122406.1445
Abstract:

为了对高压倍加器和静电加速器等低能加速器中一些具有特殊结构的轴对称静电元件进行模拟和设计,采用传输矩阵法编写了直流束的束流光学计算程序,并利用该程序对高频离子源预聚焦系统和移动式加速器中子源的束流光学系统进行了模拟和设计。程序将整个轴对称静电场区域看作厚透镜,并均分成若干个小区间,先利用其他电磁场软件计算区域内的轴上电势分布,然后根据该电势分布计算每个小区间内的束流传输情况得到束流的包络曲线。该程序可以用于计算非线性效应可忽略的复杂轴对称静电场中强流和弱流束的传输,且所需计算时间很短。

亚微秒脉冲下高梯度绝缘子的沿面闪络特性
Zhu Jun, Xia Liansheng, Chen Sifu, He Jialong, Zhang KaiZhi, Shi Jinshui, Zhang Linwen, Deng Jianjun
2012, 24: 1449-1452. doi: 10.3788/HPLPB20122406.1449
Abstract:

介绍了一种由聚酰亚胺和不锈钢叠加而成的高梯度绝缘子的实验研究工作。该绝缘子样品的直径60 mm,厚度8 mm,在脉冲宽度120 ns(FWHM)的电压脉冲加载下最高获得了接近13 MV/m的绝缘强度。研究了测试方法以及绝缘层厚度与金属层厚度的比例对高梯度绝缘子绝缘强度的影响,并与相同尺寸的普通材料绝缘子的绝缘强度进行了对比。结果表明,高梯度绝缘子的绝缘强度明显高于仅由聚酰亚胺构成的普通绝缘子。

用于太赫兹光源的准等时性储存环的设计
Zhu Jiapeng, Xu Hongliang, Feng Guangyao, Lan Jieqin
2012, 24: 1453-1457. doi: 10.3788/HPLPB20122406.1453
Abstract:

介绍了一种获得准等时性储存环的方案,即调节Lattice参数,在色散段引入负色散函数从而降低线性滑相因子,获得短束团。根据此方案设计了用于相干太赫兹光源的准等时性储存环,结果给出了线形光学函数曲线以及粒子的动力学孔径,表明了通过调节四极铁参数可以达到降低束团长度获得准等时性储存环的目的。还设计了用于准等时性储存环弯铁处的真空室的3维模型,并对其类腔体部分的本征模进行了计算,得到特性阻抗与品质因数的比值在10-3量级以下,表明类腔体部分对束流的影响很小。

条纹相机系统在激光脉冲整形测量中的应用
Wang Jigang, He Zhigang, Sun Baogen, Lu Ping, Gu Liming, Tang Leilei
2012, 24: 1461-1465. doi: 10.3788/HPLPB20122406.1461
Abstract:

针对采用脉冲堆积法进行激光脉冲整形后获取的宏脉冲,介绍了基于条纹相机观测其纵向分布的基本原理。阐述了测量系统中的硬件配置功能以及脉冲堆积原理,并描述了使用条纹相机专用软件测量激光脉冲的详细步骤和操作界面。研究了测量系统中时序控制的调试对观测脉冲堆积后的宏脉冲的影响并给出了测量结果和测量误差分析。结果表明:采用脉冲堆积法所获得的激光脉冲整形效果非常理想,整形前激光脉冲的半高全宽值约为3.82 ps,整形后约为15.3 ps,且平顶部分的脉宽为11.5 ps,上升沿和下降沿均为1.9 ps。

粒子束技术
衰减透射法测量高能X射线能谱
Wang Yi, Li Qin, Jiang Xiaoguo, Li Chenggang
2012, 24: 1466-1470. doi: 10.3788/HPLPB20122406.1466
Abstract:

研究了基于衰减透射原理的高能X射线能谱测量与重建。利用蒙特卡罗方法对神龙一号直线感应加速器的X射线源穿过不同厚度铝时的衰减透射过程进行模拟实验。解谱方法采用迭代扰动法,对不同的初始能谱估计和测量噪声水平条件下的能谱重建进行计算分析。结果表明:实验测量不包含噪声时,选择合适的初始能谱可以获得比较准确的能谱重建结果;在实验测量数据包含5.0%高斯随机噪声情况下,X射线能谱重建计算结果仍比较稳定,与真实值偏差相对较小。

二极管爆炸发射阴极等离子体的膨胀扩展
Zuo Yinghong, Wang Jianguo, Zhu Jinhui, Fan Ruyu
2012, 24: 1471-1474. doi: 10.3788/HPLPB20122406.1471
Abstract:

分析了二极管中爆炸发射产生阴极等离子体的演化特征,在考虑了阴极等离子体朝阳极膨胀运动使二极管阴阳极间距缩短这一效应的同时,还计入了阴极等离子体沿发射表面径向扩展运动对二极管有效发射面积的影响。基于Child-Langmuir定律,利用在一个四脉冲强流电子束源装置上得到的电流、电压等实验数据,假定阴极等离子体轴向膨胀和径向扩展速度近似相等,研究了阴极等离子体的膨胀扩展动力学行为。计算结果表明,阴极等离子体朝阳极的膨胀和沿径向的扩展速度为0.9~2.8 cm/s。      

增益半导体光放大器的特性
Feng Xiancheng, Duan Wenxiao, Li Han
2012, 24: 1475-1478. doi: 10.3788/HPLPB20122406.1475
Abstract:

为满足半导体光放大器(SOA)在光纤到户FTTH系统接入网中的广泛应用,提出了基于光纤光栅外腔反馈型GC-SOA结构的全光增益机制,窄线宽激光光源经可变衰减器、隔离器和光纤光栅注入到SOA中,SOA的输出光经隔离器和光纤光栅送至光谱分析仪,通过光纤光栅反馈输入SOA形成钳制激光。对GC-SOA的阈值特性、增益特性及开关特性进行分析,结果表明:当注入电流小于GC-SOA的阈值电流时,增益随注入电流的增加而增加;当注入电流大于GC-SOA的阈值电流后,其增益不再随注入电流的变化而变化,实现了SOA的增益稳定,使SOA的饱和输出功率得到了提高。

高速摄影在流体动力学不稳定性研究中的应用
Chang Lihua, Li Zuoyou, Xiao Zhengfei, Zou Liyong, Liu Jinhong, Xiong Xueshi
2012, 24: 1479-1482. doi: 10.3788/HPLPB20122406.1479
Abstract:

用高速摄影技术研究了高压气体膨胀驱动空气-水界面的瑞利-泰勒不稳定性,获得了空气-水界面的不稳定性清晰图像,得到气炮尖顶运动速度及湍流混合层高度增长速度与时间关系曲线。在横式激波管上用高速纹影诊断技术研究了激波作用空气-SF6界面的里克特迈耶-梅什科夫不稳定性,初步获得了实验图像,可清晰显示混合区变化过程。

电沉积铁层晶体结构变化的第一性原理计算
Wan Xiaobo, Tang Changhuan, Du Kai, Zhang Lin, Wang Ni, Hu Wencheng
2012, 24: 1483-1487. doi: 10.3788/HPLPB20122406.1483
Abstract:

研究了以氯化亚铁为主盐的电镀铁工艺,通过扫描电子显微镜微观形貌分析,铁镀层具有均匀致密结构,铁晶体具有较小的尺寸。通过X射线衍射测试发现,铝基底对铁镀层具有明显的诱导作用,然而随着沉积时间的增加,铁镀层逐渐趋向于Fe(211)晶面择优取向。采用第一性原理计算了不同晶面的表面能,铁晶体不同晶面的表面能依次为Fe(211)< Fe(110)<Fe(200),这很好地解释了Fe(211)晶面择优取向使体系的整体能量降低,有益于铁镀层的稳定性。

脉冲功率技术
能量响应平坦的康普顿探测器设计
Weng Xiufeng, Hei DongWei, Han Hetong, Song Zhaohui, Fu Luxiang
2012, 24: 1488-1492. doi: 10.3788/HPLPB20122406.1488
Abstract:

以开展能量响应平坦的真空康普顿探测器为目的,采用厚薄材料叠加补偿设计思想,使用蒙特卡罗方法,对真空康普顿探测器的灵敏度能量响应进行了优化设计。优化的探测器系统采用0.01,1.00 mm厚Au叠加的发射极,3 mm厚Fe前窗以及3 mm挡铅。在f40 mm准直下,实现了在0.4~7.0 MeV 能区内,探测器本征灵敏度极值变化小于10.7%。该能量响应平坦性优于当前各种常见的探测器。

宽动态范围的双正交磁光电流传感器技术
Meng Jianhua, Deng Xiangyang, Li Zeren, Peng Qixian, Yang Libing, Ouyang Kai
2012, 24: 1493-1496. doi: 10.3788/HPLPB20122406.1493
Abstract:

提出了一种新的双正交磁光电流传感器技术,该技术可解决传统磁光电流传感器测量大电流脉冲时仅根据正弦或余弦信号无法唯一确定法拉第偏转角的技术难题。在该传感器中,起偏器的透光轴与两个偏振分束器的S分量偏振方向有0与45的夹角,四路输出信号两两之间有/2的相位差。针对该传感器,提出了大电流脉冲的一种反正切函数数据处理方法,该数据处理方法具有可避开正弦函数的不灵敏区间,从而提高数据处理精度的优点。采用双正交磁光电流传感器与罗果夫斯基线圈对比测量了FP-1装置的短路电流脉冲,两种测试技术的实验结果能很好地吻合,证实该光学电流传感器可有效地测量大电流脉冲。

亚纳秒脉冲高电压测量探头
Wei Bing, Fang Dongfan, Qing Yanling, Sun Qizhi, Feng Shuping, Yang Libing
2012, 24: 1497-1501. doi: 10.3788/HPLPB20122406.1497
Abstract:

为测量紧凑型快前沿高电压脉冲源的输出电压,设计了D-dot电压探头。分别进行了刻度因素标定和频响标定,采用前沿约50 ns的高压脉冲信号对探头进行在线标定确定探头的刻度因素。将探头安装在阻抗为50 的传输线上,用亚纳秒脉冲源进行频响标定,表明该探头的响应约为150 ps。高压实验结果表明该探头能够正确获取高电压快脉冲信号,工作稳定可靠。

多原边脉冲变压器的优化设计及应用
Liu Yang, Yang Lanjun, Chen Li, Xiao Lei, Liu Jing, Zhang Haowei, Wang Wei, Kuai Bin
2012, 24: 1502-1506. doi: 10.3788/HPLPB20122406.1502
Abstract:

通过对脉冲变压器原副边回路参数、绕组结构、铁心材料的优化设计,实现了小尺寸变压器对大电流三电极开关的触发。变压器空载输出可达40 kV,增加中间储能环节后,在大电流触发管的触发极可产生百A数量级的触发电流,可以实现触发管在较低的欠压比下稳定触发。通过对脉冲变压器绝缘结构的优化设计,确保了脉冲变压器在与触发管配合过程中可以承受其输出电缆折返射造成的过电压与反灌电流。