'之'字形光栅衍射特性的数值模拟研究

摘要

新近提出的光学色散元件"之"字形光栅具有优越的衍射特征,在光谱测量和分析中具有重要的应用价值.本文基于卷积定理,采用一种新的数值计算方法对应用于X射线波段的"之"字形光栅的衍射模式进行了模拟计算,并将其衍射模式与传统光栅以及正弦光栅的衍射模式进行了比对研究,结果表明:"之"字形光栅可以将高级衍射抑制到低于一级衍射四个量级的水平,具有比传统光栅优越得多的衍射模式,与理论预期结果一致.在此基础上,又分析了实际应用过程中吸收体对X射线的吸收情况给"之"字形光栅衍射模式带来的影响,最终证实了"之"字形光栅具有较强的实际应用可行性.研究结论为"之"字形衍射光栅的物理设计提供了一种技术手段,该光栅有望代替传统黑自透射光栅应用于软X射线谱测量中.%The zigzag grating is one of the newly proposed optical dispersive elements which has an excellent diffraction characteristics and has important applications in the spectrum measurement and analysis. The simulation results of the diffraction pattern of the zigzag grating for X ray are presented using a new numerical method based on the convolution theorem, and comparison of its diffraction pattern with those of the traditional grating and sinusoidal grating are studied. It is seen from the results that all higher order diffractions of the zigzag grating are suppressed below the level of four orders of magnitude compared with the first order diffraction, which is superior to the traditional grating, being consistent with the theoretical expectations. Moreover, the impact caused by the absorber is analyzed, which eventually confirms that the zigzag grating has perfect practical application feasibility. The conclusions provide a potential alternative for the physical design of the zigzag gating, which is expected to replace the traditional transmission grating in applications to the soft X-ray spectrum measurement.