基于fresh-slice的全相干X射线自由电子激光飞秒脉冲产生原理

X射线自由电子激光(Free-Electron Laser,FEL),尤其是全相干飞秒FEL脉冲,在众多领域都有应用.依托上海软X射线自由电子激光用户装置(Shanghai Soft X-ray Free-Electron Laser User Facility,SXFEL-UF),提出了一种基于fresh-slice...     

Feasibility study on optical vortex generation at Shanghai deep ultraviolet free-electron laser

Coherent light with orbital angular momentum （OAM） is of great interest. Recently, OAM light generation by coupling a relativistic electron beam with a Gaussian mode laser pulse at the high harmonics of a helical undulator has been demonstrated experimentally. In this paper, the possibility of delivering coherent OAM light at the 3rd harmonic of the Gaussian mode seed laser is discussed for the Shanghai deep ultraviolet free- electron laser （SDUV-FEL）. Considerations are given on the experiment setup, the expected performance and the possible measurement method.     

大连极紫外相干光源

先进光源的发展在前沿科学研究中发挥的作用越来越重要。近十年来,飞速发展的自由电子激光技术为科学家们提供了探索未知世界、发现新科学规律和实现技术变革的重要工具。建成的大连极紫外(EUV)相干光源的运行波段为50～150nm,单脉冲能量大于100μJ,且可提供10-12 s和10-13 s量级的超快激光脉冲,是我国第一台自由电子激光用户装置,并且是国际上唯一运行在极紫外波段的自由电子激光用户装置,在世界范围内为用户提供具有高峰值亮度和超短脉冲的极紫外激光。大连EUV相干光源是由国家自然科学基金委资助、由中国科学院大连化学物理研究所和上海应用物理研究所共同承担的重大科学仪器研制项目,目标是打造一个以先进极紫外光源为核心、主要用于能源基础科学研究的光子科学平台。     

Three-dimensional numerical investigations of the laser-beam interactions in an undulator

Laser-beam interaction in an undulator is commonly suggested in the development of free electron laser （FEL） schemes. In this paper, a three-dimensional algorithm is developed to assist in laser-beam interaction simulation in an undulator, which is built     

HGHG自由电子激光时间相干性研究

时间相干性是外种子型自由电子激光(FEL)对于自发辐射自放大(SASE)FEE具有的重要优势之一。利用自制的迈克尔逊干涉仪测量了600 nm(二次谐波)和400 nm(三次偕波)高增益谐波放大(HGHG)FEL的时间相干性,分析不同延迟时间处的干涉图样条纹可见度,得到了600 nm和400 nm HGHG自由电子激光的相干长度,分别为119±6.7 fs和112±16.9 fs。通过与光谱测量和理论计算结果进行比较,进一步验证了实验测量的准确性。结果表明HGHG自由电子激光继承了种子激光的相干性特点,这与理论预测结果相一致。