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Study of pico second movie of plasma interaction with optical vortex and particle acceleration

等离子体与光学涡旋和粒子加速相互作用的皮秒电影研究

基本信息

批准号：
13480128
负责人：
MIYANAGA Noriaki
金额：
$ 9.22万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

1) Generation of ultra-short-pulse optical vortex using spiral phase shifter: A spiral phase shifter was fabricated by coating a 16-steppatterned SiO* onto a glass substrate. The phase distribution was in good agreement with that predicted by the computed hologram, and then an optical vortex (Laguerre-Gaussian beam with a topological charge of 1) was successfully obtained.2) Imaging with sub-ps time resolution: A 130-fs ultra-short Ti: sapphire laser pulse was frequency doubled. Then optical probe system was constructed using this UV pulse for measuring short-life plasmas by shadowgraphy and interferometer techniques. The propagation of ultra-short-pulse laser light and the dynamics of plasma formation were observed using this probing system, and their dependence on laser phase/polarization distributions was studied.3) Generation of longitudinal electric field from laser: A linearly polarized light was converted to axially symmetric polarization (radial polarization and azimuthal polarization) with an efficiency greater than 90% using a polarization distributed plate based on an optical rotatory of liquid crystal. A longitudinal electric field of 10*V/m was observed near a focal spot of 0.45-MW radially polarized Nd: YAG laser. Thus 0.1TV/m can be realized using a TW class high power laser.4) Particle acceleration with optical vortex and radial polarization: Ti: sapphire laser pulse of 0.5-1TW was focused onto a solid or gaseous target. The measured electron spectra suggest that these special laser modes can enhance the amount of forward accelerated electrons especially in high energy component.5) Particle simulation: A particle simulation code has been newly developed for the analysis of the effects caused by the phase/polarization distribution. This code showed that the substantial increase of high-energy electrons for combining the Laguerre-Gaussian beam with circular polarization.

1）使用螺旋移相器产生超短脉冲光学涡旋：通过在玻璃基板上涂覆16阶图案的SiO*来制造螺旋移相器。相位分布与计算全息图预测的非常吻合，成功获得了光学涡旋（拓扑电荷为1的拉盖尔高斯光束）。2）亚皮秒时间分辨率成像：将130 fs超短Ti：蓝宝石激光脉冲倍频。然后使用该紫外脉冲构建光学探针系统，通过阴影照相术和干涉仪技术测量短寿命等离子体。使用该探测系统观察了超短脉冲激光的传播和等离子体形成的动力学，并研究了它们对激光相位/偏振分布的依赖性。3）激光产生纵向电场：使用基于偏振分布板的偏振分布板将线偏振光转换为轴对称偏振（径向偏振和方位偏振），效率大于90％液晶旋光器。在0.45MW径向偏振Nd:YAG激光器焦点附近观察到10*V/m的纵向电场。因此，使用TW级高功率激光器可以实现0.1TV/m。4)利用光学涡旋和径向偏振的粒子加速：将0.5-1TW的Ti：蓝宝石激光脉冲聚焦到固体或气体目标上。测量的电子光谱表明，这些特殊的激光模式可以增加向前加速的电子数量，特别是在高能成分中。5）粒子模拟：新开发了粒子模拟代码，用于分析相位/偏振分布引起的影响。该代码表明，拉盖尔高斯光束与圆偏振相结合时高能电子的大幅增加。