长春光机所软X射线成像望远镜和同步辐射光束线研制技术的发展现状

本文概述了我所12年(1978～1990)来在软X射线成像望远镜和同步辐射光束线以及短波段光学中有关单元技术研究的发展现状。指出了限制软X射线光学技术发展的主要问题,提出发展软X射线成像和同步辐射反射光学技术应开展的主要研究工作。     

软X射线稀有气体电离室

软X线稀有气体电离室作为软X线波段绝对探测器，是通过测量光电离子流得出光谱辐射强度。介绍我们研制的1m软X射线稀有气体电离室的工作原理及结构，测出空阴极光源辐射出的HeⅡ25．6nm离子线及Henke源Cka4．47nm的强度随电离室工作气压的变化外推出零气压下谱线光谱辐射强度，最终得出谱线的绝对光谱辐射强度。     

同步辐射X射线双晶单色仪能量扫描

晶体单色仪是X射线光束线上的关键设备,它用晶体作为色散元件,衍射、分离具有连续光谱的同步辐射,向用户提供一定带宽的X射线单色光.在合肥同步辐射装置上的晶体单色仪,使用两块Si(111)晶体,按(⁺n,^-n)无色散排列,通过一台专门研制的L型联动装置,仅一维简单的Bragg角转动,便可保证在动态能量扫描过程中,两晶体衍射面始终平行,且输出的单色光束与入射光束的相对位置不变.本文重点讨论的是用于合肥晶体单色仪上的能量扫描装置.     

软X射线稀有气体电离室

软X线稀有气体电离室^[1][2]作为软X线波段绝对探测器,是通过测量光电离子流得出光谱辐射强度。介绍我们研制的1m软X射线稀有气体电离室的工作原理及结构,测出空阴极光源辐射出的HeⅡ25.6nm离子线及Henke源C^k_α4.47nm的强度随电离室工作气压的变化外推出零气压下谱线光谱辐射强度,最终得出谱线的绝对光谱辐射强度。     

软X射线多层膜反射镜的设计、制备与检测

本文提出一种图像直观、结果可靠的软X线多层膜设计方法,讨论了与软X射线多层膜制备有关的基板选择,膜厚控制等工艺问题。给出Mo/Si软X射线多层膜小角度衍射及171Å、231Å及256Å处软X射线反射率的测试结果,并对软X射线多层膜工作做了展望。     

软X射线电离室

软 X 射线稀有气体电离室作为软 X 射线波段绝对探测器,是通过测量光电离子流得出光谱辐射强度.并详细介绍我们研制1米软 X 射线稀有气体电离室的工作原理及结构,测出空阴极光源辐射出的HeⅡ25.6nm 离子线及 Henke 光源辐射出的 CK_α 4.47nm 线的强度随电离室工作气压的变化,外推出零气压下谱线光谱辐射强度,最终得出谱线的绝对光谱辐射强度.     

使用平行束软X光透镜的深亚微米X射线光刻

使用本实验室研制的整体平行束软X光透镜作为准直器和电子枪软X光源相配,作成了平行束软X光源,用此平行束软X光源进行了深亚微米X射线光刻实验。刻出了1.0μm～0.2μm的线条。文中对实验装置和光刻结果作了简要的介绍。     

用Si光电二极管标定软X射线探测器

为了实现软X射线波段光源相对光谱分布的测量,引进了一种利用新型软X射线波段传递标准探测器—Si光电二极管对软X射线探测器进行标定.标定了软X射线波段光谱测量实验中常用的探测器—通道电子倍增器在放大电压为1.3kV时的量子效率,并对实验结果进行了分析,得出在8～30nm波段内探测器标定误差为5.7%～8.9%.     

软X射线界面传输特性及应用研究

对软X射线与界面相互作用的规律进行初步研究,给出了软X射线界面散射的一级近似一般理论推导,从中给出了粗糙界面软X射线的散射传输特性,表明在粗糙表面上软X射线的镜向反射系数,需要做与粗糙度有关的数学修正。作为形式上的一种方法,本文还给出了粗糙表面对软X射线全反射的动力学模型,以及一维软X射线散射测量粗糙度原理。通过实验测量了λ=243Å,256Å时具有超光滑表面的Mo,Si样品之反射率和λ=44.6Å时石英超光滑样品的反射率。采用镀碘化铯的方法,使“真空紫外-软X光反射率计”的可测量短波长从200Å降至10Å.对44.6Å进行了散射测量,可以明显看到软X射线的非正常反射现象;还对积分散射测粗糙度方法进行了初步研究。最后给出了X线聚焦装置的理论公式和设计实例。     

双道X射线分光光谱仪及其与扫描电子显微镜的匹配

本X光谱仪是一种线性全聚焦弯晶谱仪。装备在扫描电镜上后,可使之兼具电子探针X光微区分析仪的功能。本文重点讨论了X光光谱仪的几何精度、分光晶体的制备、光谱仪与电子光学镜筒的匹配衍射峰值强度的提高、本底噪音的减低以及同轴光学显微镜的匹配等问题。X光谱仪的总几何精度应为±1′,重复精度为6″。实际结果表明,元素分析范围为B~5(Be~4)～U~(92);波长分辨率△λ/λ为1～5×10~(-3)(Na~(11)～U~(92))及1～5×10~(-2)(B~5～F~9),可分开Cu,Fe,Ti等元素的K_(α1,α2)谱线,Ti-6A1-4V合金中VK_(α1),VK_(α2)及TiK_β谱线;波长重复性为0.00014A;探测限对Na~(11)～U~(92)为10~(-3)％量级,B~5～F~9为10~(-2)％量级。     

Effect of process parameters in nanosecond pulsed laser micromachining of PMMA-based microchannels at near-infrared and ultraviolet wavelengths

This paper presents investigations on the effects of nanosecond laser processing parameters on depth and width of microchannels fabricated from polymethylmethacrylate (PMMA) polymer. A neodymium-doped yttrium aluminium garnet pulsed laser with a fundamental wavelength of 1,064 nm and a third harmonic wavelength of 355 nm with pulse duration of 5 ns is utilized. Hence, experiments are conducted at near-infrared (NIR) and ultraviolet (UV) wavelengths. The laser processing parameters of pulse energy (402–415 mJ at NIR and 35–73 mJ at UV wavelengths), pulse frequency (8–11 Hz), focal spot size (140–190 μm at NIR and 75 μm at UV wavelengths) and scanning rate (400–800 pulse/mm at NIR and 101–263 pulse/mm at UV wavelengths) are varied to obtain a wide range of fluence and processing rate. Microchannel width and depth profile are measured, and main effects plots are obtained to identify the effects of process parameters on channel geometry (width and depth) and material removal rate. The relationship between process variables (width and depth of laser-ablated microchannels) and process parameters is investigated. It is observed that channel width (140–430 μm at NIR and 100–150 μm at UV wavelengths) and depth (30–120 μm at NIR and 35–75 μm at UV wavelengths) decreased linearly with increasing fluence and increased non-linearly with increasing scanning rate. It is also observed that laser processing at UV wavelength provided more consistent channel profiles at lower fluences due to higher laser absorption of PMMA at this wavelength. Mathematical modeling for predicting microchannel profile was developed and validated with experimental results obtained with pulsed laser micromachining at NIR and UV wavelengths.     

A two-wave 1064/532-nm diode-pumped pulse-periodic YAG:Nd laser

A compact 1064/532-nm diode-pumped pulse-periodic YAG:Nd laser is described. Its parameters are as follows: the wavelength is 1064 nm, the pulse energy is 1.2 J, the pulse duration is 5 ns, the pulse repetition rate is 100 Hz, and the beam divergence is ≤1.6 mrad. The laser light efficiency is 12%, and the full efficiency of the laser system is 4%. Two lasing modes are realized in the laser: at the fundamental frequency and with the frequency conversion into the second harmonic at a wavelength of 532 nm and a pulse energy of 0.3 J.     

High repetition rate laser produced soft x-ray source for ultrafast x-ray absorption near edge structure measurements

Recent progress in high intensity ultrafast laser systems provides the opportunity to produce laser plasma x-ray sources exhibiting broad spectrum and high average x-ray flux that are well adapted to x-ray absorption measurements. In this paper, the development of a laser based x-ray absorption near edge structure (XANES) beamline exhibiting high repetition rate by using the Advanced Laser Light Source (ALLS) facility 100 Hz laser system (100 mJ, 35 fs at 800 nm) is presented. This system is based on a broadband tantalum solid target soft x-ray source and a grazing incidence grating spectrometer in the 1-5 nm wavelength range. To demonstrate the high potential of this laser based XANES technique in condensed matter physics, material science, or biology, measurements realized with several samples are presented: VO2 vanadium L edge, Si3N4 nitrogen K edge, and BPDA/PPD polyimide carbon K edge. The characteristics of this laser based beamline are discussed in terms of brightness, signal to noise ratio, and compared to conventional synchrotron broadband x-ray sources which allow achieving similar measurements. Apart from the very compact size and the relative low cost, the main advantages of such a laser based soft x-ray source are the picosecond pulse duration and the perfect synchronization between this x-ray probe and a laser pulse excitation which open the way to the realization of time resolved x-ray absorption measurements with picosecond range time resolution to study the dynamics of ultrafast processes and phase transition.     

Controlled Synthesis and Optical Properties of Pure Gold Nanoparticles

Abstract

Gold nanoparticles were synthesized by laser ablation of a gold metallic disc at wavelengths of 532 nm and 355 nm with 7 ns pulse duration in the pure water. The colloidal gold nanoparticles were characterized by ultraviolet-visible absorption spectroscopy, transmission electron microscopy, and fluorescence spectrometry. The presence of a surface plasmon resonance peak around ～ 524 nm indicates the formation of gold nanoparticles. The formation efficiencies of gold nanoparticles in colloids were found to increase when ablating the gold metallic disc with a laser having a longer wavelength. The size distributions of the gold nanoparticles thus produced were measured by transmission electron microscopy. A reduction in mean diameter of the particles was observed with a decrease in the laser wavelength under the irradiation at a high fluence of 25 mJ/pulse. The fluorescence spectroscopy demonstrated that these gold nanoparticles are fluorescent, showing a strong blue emission intensity at 458 nm.     

水靶激光等离子体光源11~20 nm波段光谱实验

实验以水为靶材,Nd:YAG激光器为照射激光构成激光等离子体光源,产生软X射线-极紫外辐射。利用McPHERSON 247型掠入射软X射线-真空紫外单色仪、AXUV100硅光电二极管,测量了11~20 nm波段水靶激光等离子体光源的光谱。实验表明,在11~20 nm波段水靶激光等离子体光源存在多条线谱,均由水中氧离子电子跃迁产生。所用单色仪光谱分辨率Δλ≤0.075 nm,波长扫描间隔0.5 nm。另外,采用在喷嘴处加热的办法,很好地解决了水进入真空系统后绝热膨胀与蒸发过程中温度骤降而结冰的问题,有效地抑制了喷射距离缩短,克服了等离子体对喷嘴腐蚀严重的问题。     

Experimental investigation of laser-produced-plasma EUV source based on liquid target

1Introduction LPPsourcesholdgreatpromiseasbright sourcesofextreme ultraviolet(EUV)andsoft X rayradiationforapplicationssuchasprojec tionlithography[12],microscopy[3].However,withLPPsource,theapplicabilityisrestricted duetotheemissionsofdebris,whichmaydam agesensitivemetrologycomponentsclosetoLPP source.Toreducethedebris,methodsconcen tratingontwoaspectshavebeenappliedbefore theappearanceofgasandliquidtargets.Oneas pectistoreducetheamountofdebris,theother istointerdictthedebrisfromreaching…     

垂直腔面发射激光端面泵浦的高能量调Q Nd:YAG激光

采用垂直腔面发射激光端面泵浦Nd∶YAG获得了高能量的1 064 nm调Q激光输出。与边发射半导体激光相比,垂直腔面发射激光具有各向发散角相同、波长随温度漂移小等优点,更适合用作泵浦源以产生高效率、结构紧凑的激光。泵浦能量为200 mJ时,产生了最高45 mJ的1 064 nm激光输出,光光转换效率达到22.5%,激光脉宽为8 ns,发散角为1.2 mrad。基于模拟计算优化了Nd3+掺杂浓度,通过采用低浓度的Nd∶YAG晶体减小泵浦端面增益,从而有效抑制了影响调Q激光能量提高的自激振荡,为获得高能量的端面泵浦调Q激光输出提供了有效的技术手段。     

A narrow-band source of ultraviolet radiation for laser isotope separation

A pulsed tunable laser source of ultraviolet radiation with a linewidth of <400 MHz, a pulse duration of 9 ns, and a pulse repetition rate of 11 kHz pumped by a copper-vapor laser has been developed. Its average output power at a wavelength of 276 nm is 1.5 W. A system intended for laser isotope separation contains a master oscillator based on a dye laser, two amplifying stages with an average output radiation power of 4.5 W at a wavelength of 553 nm, and a radiation-frequency doubler on a BBO crystal. The master-oscillator laser is built according to a scheme with a diffraction grating positioned at an angle close to the glancing angle, a prism beam expander, and an air-filled hermetically sealed Fabry-Perot etalon. The long-term frequency stability of the output radiation is 10 MHz/h.     

准基模纯风冷激光二极管泵浦Nd∶YAG激光器

介绍一种纯风冷激光二极管泵浦的脉冲Nd∶YAG激光器,单脉冲能量250mJ,重复频率25Hz,脉冲宽度7ns,光光转换效率13.6%。激光器输出为准基模,垂直和水平方向的M2值测量结果分别为2.81和4.09。同样结构下将风冷系统换成风冷水冷结合方式,激光器脉冲能量345mJ,重复频率提高到50Hz,光光转换效率上升为15.2%。两种形式的激光器连续工作时间5min,并进行了高温+55℃和低温-25℃的环境试验。     

小型的高精度软X射线-极紫外反射率计

针对探月二期工程中的有效载荷之一极紫外相机中的多层膜光学元件高精度反射率测量的需要,建立了一台使用液体靶激光等离子体光源的小型软X射线-极紫外波段反射率计。该反射率计主要由激光等离子体光源、Mcpherson 247动狭缝掠入射单色仪及相关的数据采集系统组成。单色仪波段范围1-125nm,光谱分辨率小于0.08nm。无碎屑的液体靶激光等离子体光源的使用避免了光学元件的损坏,而动狭缝掠入射单色仪的使用则提高了光谱分辨率和波段范围。使用该反射率计实测了工作波长为13.5nm和30.4nm的Mo/Si多层膜的反射率,测量结果表明测量重复性优于±0.5%。