微聚焦菲涅耳波带板聚焦特性研究

通过激光轰击Ti平面靶，用微聚焦菲涅尔波带板做成像器，测到了在放大倍数为66倍时X射线焦斑图像.利用Fresnel-Kirchhoff衍射积分公式数值模拟了微聚焦菲涅尔波带板的点扩展函数，模拟结果表明该微聚焦菲涅尔波带板在两倍焦距处强聚焦.改变物距和像距但保持透镜的物像距公式，也可得到类似的结果.模拟和实验表明微聚焦波带板可以应用于X射线点对点成像，实现激光等离子体X射线高空间分辨成像. 关键词： 菲涅尔波带板 Fresnel-Kirchhoff衍射 数值模拟 点扩展函数

Study on the focus performance of micro-focus Fresnel zone plate

The performance of micro-focus Fresnel zone plate(MFZP) with the outermost width of 150nm is tested using the Ti spectral line. Experimental data indicates that the image of pinhole with diameter of 125μm fully responses to a pixel of the X-ray CCD camera. Furthermore，the X-ray focal spot is tested with a magnification of 66 by using laser striking the Ti planar target. The MFZP's point spread function is simulated with the integral formula of Fresnel-Kirchhoff diffraction. The simulated results indicate that the MFZP strongly focuses at double foci. The same results are obtained when the object distance and image distance change but keeping the relation of the lens unchanged. The simulation and the experiment indicate that MFZP can be applied to point-to-point imaging of X-ray to realize high spatial resolution imaging for the laser plasmas.