提出了利用多层膜聚光镜提高Schwarzschild显微镜成像均匀性的方法。设计了聚光镜的光学结构, 使80%的等离子体辐射能量会聚在约08 mm直径的范围内。根据成像系统的工作波长和光线在聚光镜表面的入射角度, 设计了Mo/Si周期多层膜, 制备了聚光镜光学元件, 膜层周期厚度为9.64 nm, 周期数为30, 对18.2 nm波长的峰值反射率为51.7%。利用所设计的聚光镜作为照明系统, 对Schwarzschild物镜进行了网格成像实验。结果表明:在1.2 mm视场内可以实现2.5 μm的空间分辨力, 并且完全消除了物镜中心遮拦所造成的像面光强分布不均匀性。

The method for improving the uniformity of the image using multilayer films condenser is proposed. The optical structure of the condenser is designed, which concentrates 80% energy radiated by plasma to about 0.8 mm diameter range. Based on the system’s wavelength and incidence angle of light, the Mo/Si multilayer films with period of 9.64 nm and layers of 30 is designed and the coatings are deposited with magnetron sputtering. The reflectivity of optical elements at 18.2 nm is 51.7%. The grid backlit by EUV rays focused using condenser is imaging via Schwarzschild microscope on CCD. The results show that spatial resolution of 2.5 μm can be achieved in the 1.2 mm field, and the non-uniformity of image caused by the obscuration of objective is eliminated absolutely.