以软X射线双频光栅作为剪切干涉元件,研究了剪切干涉法在激光等离子体诊断实验中的应用.为提高实验成功率,研究了双频光栅栅线的平行度及光栅效率.根据软X射线双频光栅栅线平行度与剪切干涉系统的干涉图像的关系,理论计算得出光栅平行度的指标要求.在全息曝光工艺中,通过衍射光斑位置检测法和莫尔条纹法确认光栅平行性,保证光栅平行度达到0.01°.利用合肥国家同步辐射实验室计量站对双频光栅的两组-1级衍射效率进行测试.测试结果显示,光栅平行性满足系统要求,光栅的两组-1级衍射效率均达到10％.软X射线双频光栅剪切干涉实验结果表明,双频光栅平行度及衍射效率满足激光等离子体诊断实验需求.%Applications of a soft X-ray double frequency grating shearing interferometer to laser plasma diagnostics were explored by using a soft X-ray double frequency grating as the shearing interferometric element.To improve the success rate of experiment,this paper analyzed the line parallelism and diffraction efficiency of the double frequency grating.On the basis of the relationship between the line parallelism of the double frequency grating and the interferogram of shearing interferometer,it calculated the technical requirements of line parallelism of the grating.The fabrication method was described,the line parallelism of the grating was realized with the diffraction spot position monitoring,and the moiré fringe method was applied in line parallelism judgment for the grating.A double frequency grating with line parallelism less than 0.01° was fabricated.The two groups of diffraction efficiencies of-1 order for the grating were examined in spectral radiation standard and metrology beamline of Hefei National Synchrotron Radiation Laboratory,and the results show both of them are over 10％ at 13.9 nm.A shearing interferometer was set up for dense plasma diagnostics,whose results demonstrate that the parallelism and diffraction efficiency of the double-frequency grating can meet the experimental requirements.
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