Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Shanghai Institute of Laser Plasma, Shanghai 201800, China
In high power laser facility for inertial confinement fusion research, final optics assembly (FOA) plays a critical role in the frequency conversion, beam focusing, color separation, beam sampling and debris shielding. The design and performance of FOA in SG-II Upgrade laser facility are mainly introduced here. Due to the limited space and short focal length, a coaxial aspheric wedged focus lens is designed and applied in the FOA configuration. Then the ghost image analysis, the focus characteristic analysis, the B integral control design and the optomechanical design are carried out in the FOA design phase. In order to ensure the FOA performance, two key technologies are developed including measurement and adjustment technique of the wedged focus lens and the stray light management technique based on ground glass. Experimental results show that the design specifications including laser fluence, frequency conversion efficiency and perforation efficiency of the focus spot have been achieved, which meet the requirements of physical experiments well.
final optics assembly high power laser facility inertial confinement fusion. High Power Laser Science and Engineering
2018, 6(2): 02000e14
Author Affiliations
Abstract
1 National Laboratory on High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Key Laboratory of High Power Laser and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
3 Shanghai Institute of Laser Plasma, China Academy of Engineering Physics, Shanghai 201800, China
The Shen-Guang II Upgrade (SG-II-U) laser facility consists of eight high-power nanosecond laser beams and one short-pulse picosecond petawatt laser. It is designed for the study of inertial confinement fusion (ICF), especially for conducting fast ignition (FI) research in China and other basic science experiments. To perform FI successfully with hohlraum targets containing a golden cone, the long-pulse beam and cylindrical hohlraum as well as the short-pulse beam and cone target alignment must satisfy tight specifications (30 and $20~\unicode[STIX]{x03BC}\text{m}$ rms for each case). To explore new ICF ignition targets with six laser entrance holes (LEHs), a rotation sensor was adapted to meet the requirements of a three-dimensional target and correct beam alignment. In this paper, the strategy for aligning the nanosecond beam based on target alignment sensor (TAS) is introduced and improved to meet requirements of the picosecond lasers and the new six LEHs hohlraum targets in the SG-II-U facility. The expected performance of the alignment system is presented, and the alignment error is also discussed.
laser drivers petawatt lasers spherical hohlraum target alignment target area High Power Laser Science and Engineering
2018, 6(1): 01000e10
苏州大学信息光学研究所， 江苏 苏州 215006
基于外腔半导体可调谐激光器(ECDL)设计了一种结构紧凑的移频激发差分拉曼光谱(SERDS)法的多波长光源，具有15 nm的波长调谐范围，优于0.2 nm的线宽以及最大80 mW的输出功率。提出用多重约束反卷积算法对SERDS差分光谱进行复原处理，可有效抑制噪声。应用SERDS方法对苏丹红I号、罗丹明B、三聚氰胺、乌洛托品等非法食品添加剂进行了测量，证明该方法不仅能很好地去除荧光背景，而且能大幅提高检测信噪比。
光谱学 拉曼光谱 荧光抑制 移频激发 外腔半导体激光器 反卷积
苏州大学 信息光学工程研究所，江苏 苏州 215006
拉曼光谱检测常常受到荧光的干扰，影响了该技术的推广应用。移频激发差分拉曼光谱方法（SERDS方法）已被证明是一种有效的荧光抑制方法。SERDS实现荧光抑制的关键在于其特殊的激光光源，不仅要求其输出多个相近的波长，而且要求输出的激光功率较高、光谱线宽窄。采用Littrow光栅外腔半导体激光器原理设计实现了一种低成本、便携式的激光光源，可以在15nm的调谐范围内输出多个波长，光谱线宽小于0.2nm，输出功率可达80mW，适合用作移频激发差分拉曼光谱方法的多波长光源，实现拉曼光谱检测中对荧光干扰的抑制。
荧光抑制 移频激发差分拉曼光谱 外腔半导体激光器 fluorescence suppression shifted excitation Raman difference spectroscopy external cavity diode laser
苏州大学 信息光学工程研究所, 江苏 苏州215006
为了降低CCD噪声, 提高信噪比, 根据噪声的特性, 提出用CCD的Binning技术用于噪声的抑制。理论上推导了水平Binning和垂直Binning两种情况下信噪比提高的公式。利用MATLAB语言编程对垂直Binning的几种情况进行仿真, 仿真结果表明, Binning可以有效提高信噪比, 信噪比提高的理论值和计算值基本相符, 对Binning可能带来的电荷饱和也进行了讨论。
信噪比 CCD CCD Binning Binning signal to noise ratio MATLAB MATLAB
苏州大学信息光学工程研究所,江苏 苏州215006
拉曼光谱仪已经广泛应用于分析化学、安全检查、生物医学等领域,小型化、智能化是其发展的重要方面。便携式拉曼光谱仪具有体积小、检测方便等特点,便于现场测量与分析。目前,在药物检测、机场安检、爆炸物分析等领域便携式拉曼光谱仪受到青睐。对国内外产业化和实验室的便携式光谱仪的发展进行了比较全面的综述,最后对便携式拉曼光谱仪的发展趋势进行了总结与展望。
便携式拉曼光谱仪 激发光源 拉曼光纤探头 微型光谱仪 portable Raman spectrometer excitation source fiber optical Raman probe micro spectrometer
1 中国科学院上海光学精密机械研究所高功率激光物理联合实验室， 上海 201800
2 中国工程物理研究院上海激光等离子体研究所， 上海 201800
提出一种可实现351 nm波长激光高通量传输的终端光学组件(FOA)的物理设计方案，研究了设计优化方法，并利用神光Ⅱ装置第九路系统开展了实验研究。实验共进行了33发激光发射：激光光束净口径310 mm，时间脉冲宽度3 ns，1053 nm波长激光能量1000～4500 J。实验获得最高三次谐波转换效率69.6%和351 nm波长激光传输通量3.76 J/cm2，同时监测到高通量激光传输引起的动态环境污染物颗粒变化数和光学元件激光诱导损伤等现象。实验结果表明，通量密度约为3 J/cm2@351 nm的光学元件损伤主要是由激光传输散射鬼光束辐照材料所激发的污染物所致。
激光器 高功率激光装置 终端光学组件 三倍频激光 激光诱导损伤
