排序方式: 共有49条查询结果,搜索用时 15 毫秒
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阿秒超紫外线(extreme ultra-violet, XUV)与飞秒超短激光脉冲共同激发惰性气体原子产生光电子,其终态能量与光电子产生时刻即激光相位有关. 介绍光电子的激光相位确定法,并利用光电子能谱本身(其比例谱),计算出待测窄带XUV脉冲的强度时间结构. 研究表明,在与激光线性极化方向成0°或180°方向测量得到的光电子能谱动态范围大,容易解谱. XUV脉冲的时间宽度的测量范围为半个激光振荡周期,时间分辨率主要取决于测量系统的时间晃动和控制精度.
关键词:
光电子能谱
相位确定法
变换方程
脉冲强度时间结构 相似文献
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庞丹阳叶沿林 江栋兴郑涛王全进 李智焕李湘庆葛愉成 吴翠娥张高龙 胡青元王佳 A.Ozawa Y.Yamaguchi R.Kanungo D.Fang I.Tanihata 《中国物理快报》2004,21(11):2151-2154
The differential cross sections of quasielastic scattering of a 25 MeV/u ^6He from ^9Be target have been measured.The double-folding model approach is applied to generate the real part of the optical potential. The imaginary potential parameters as well as some of the real potential parameters are studied in comparison with the experimental data. The effect of the unstable nucleus is discussed. 相似文献
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庞丹阳叶沿林 郑涛李智焕 李湘庆葛愉成 华辉吴翠娥 楼建玲卢飞 范凤英A. Ozawa Y. Yamaguchi R. Kanungo D. Fang I.Tanihata 《中国物理快报》2007,24(10):2785-2788
The inclusive differential cross sections of the ^7 Li nucleus in a reaction induced by ^6He on a ^9Be target are measured at an incident energy of 25 MeV/nucleon. Finite-range distorted-wave Born approximation calculations suggest that these ^7 Li particles are formed in a direct single-proton pickup reaction ^9Be(^6He,^7 Li)^8Li. The experimental data can be well reproduced by taking into account of the contributions of both the ground states and the first excited states of ^7Li and ^8Li. 相似文献
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Quantitative investigations are made for the laser-duration dependence of the emission properties of high-order harmonic generation (HHG). HHG emission properties produced by few-cycle lasers show some useful characteristics. The cutoff energy is less than that by laser for infinite duration. The single energy distribution pulse decreases much faster than its duration as the laser duration grows. A two-cycle laser with carrier-envelope phase of 0° can produce a single distribution pulse peaked at the laser carrier phase 1.22 rad and spanned 1.18 rad with the cutoff energy 2.9Up + Ip and a bandwidth 0.63Up, where Up is the ponderomotive potential of the laser field and Ip is the atomic ionization potential. 相似文献
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楼建玲 李智焕 叶沿林 江栋兴 华辉 李湘庆 张双全 郑涛 葛愉成 孔赞 吕林辉 李琛 卢飞 范凤英 李忠宇 曹中鑫 马立英 Faisal 徐瑚珊 胡正国 王猛 雷相国 段利敏 肖志刚 黄天衡 付芬 章学恒 郑川 余玉洪 涂小林 张亚鹏 杨彦云 张宏斌 唐彬 田育林 欧阳珍 黄美容 徐治国 岳珂 高启 《中国物理 C》2008,32(Z2):41-43
The β-delayed neutron and γ spectra of neutron-rich nucleus 21N using β-γ and β-n coincidence measurements were presented in this paper. Thirteen new neutron groups ranging from 0.28 MeV to 4.98 MeV and with a total branching ratio 88.7±4.2% were observed. One γ transition among the excited states of 21O, and four γ transitions among the excited states of 20O were identified in the β decay chain of 21N. The ungated half-life of 83.8±2.1 ms was also determined for 21N. 相似文献
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报告由不同脉冲宽度(半高宽,FWHM)和不同载波-包络相位(CEP,Φ)的激光产生的高次谐波辐射能量输出时间特性即发射特性的研究结果. 计算表明,由宽度为几个周期的激光产生的高次谐波辐射的截止能量明显低于由无限长脉冲宽度激光产生的截止能量ωmax=3.17Up+Ip(其中ωmax为光子角频率,Up和Ip分别为激光有质动力势和原子的电离能). 例如,由两周期(FWHM),Φ=15°的激光产生的高次谐波辐射的截止能量为ωmax=2.90Up+Ip,此时发射特性单脉冲(即分布单脉冲)具有最大的能量带宽0.86Up. 脉冲中心位置的载波相位和时间宽度分别为0.94rad(弧度)和1.29rad. 而该激光脉冲在Φ=-75°时能产生截止能量为ωmax=2.70Up+Ip,最大能量带宽为0.70Up的双分布脉冲,其中心位置分别为-0.58rad和2.43rad,宽度分别为1.22rad和1.33rad. 随着激光脉冲宽度的增加,分布单脉冲的能量带宽比时间宽度下降得更快. 对于一定宽度的激光脉冲,所产生的分布单脉冲的能量带宽和时间宽度的CEP依赖性显示出180°的周期结构. 利用这个有趣的特点,在实验上可以通过调节CEP来选择分布脉冲的能量参数,也可用来定位和控制阿秒脉冲的时间参数. 理论分析指出,只要选择合适的阿秒X射线能量带宽,CEP不稳定性对于光电子谱和测量结果的影响将大为降低,甚至在最大程度上消除这种影响. 这些研究结果不仅有助于在物理上深入了解高次谐波辐射的动力学过程,而且对于进一步在实验上优化和选择阿秒单脉冲和双脉冲具有重要的参考和指导意义.
关键词:
高次谐波产生
鞍点方法
谐波发射特性
分布脉冲 相似文献
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臧宏亮 叶沿林 李智焕 王建松 楼建玲 李奇特 葛愉成 杨晓菲 李晶 蒋伟 冯俊 刘强 杨彪 陈志强 刘洋 吴鸿毅 牛晨阳 李晨光 王春光 王翔 刘威 高见 余翰舟 马军兵 马朋 白真 杨彦云 金仕纶 卢飞 《中国物理C(英文版)》2018,42(7):074003-074003
An experiment for p(~(14)C,~(14)C~*→~(10)Be+α)p inelastic excitation and decay was performed in inverse kinematics at a beam energy of 25.3 Me V/u.A series of~(14)C excited states,including a new one at 18.3(1)Me V,were observed which decay to various states of the final nucleus of~(10)Be.A specially designed telescope system,installed around zero degrees,played an essential role in detecting the resonant states near theα-separation threshold.A state at 14.1(1)Me V is clearly identified,being consistent with the predicted band-head of the molecular rotational band characterized by theπ-bond linear chain configuration.Further clarification of the properties of this exotic state is suggested by using appropriate reaction tools. 相似文献