13.5nm Schwarzschild显微镜系统及成像实验

摘要

研制了工作波长为13.5 nm的Schwarzschild成像显微镜.从共轴两镜系统的基本理论出发,通过消除三级球差、彗差和像散设计了Schwarzschild物镜的光学初始结构,计算了物镜的光学传递函数.结果表明,物镜在士0.3 mm视场内像方空间分辨率可达550 lp/mm.根据工作波长和镜面的入射角度设计了Mo/Si周期多层膜反射镜,制作了Schwarzschild显微镜光学元件,多层膜元件对13.5 nm波长的反射率为61％.为了消除可见光和紫外光对系统成像的影响,设计并制备了材料为Zr,Si和Si3 N4的滤波片,该滤波片在13.5 nm处的透过率为21.1％.利用激光等离子体光源对60 lp/mm网格进行了成像实验,结果表明,系统在0.5 mm视场内的分辨率优于3μm,结论认为CCD探测器分辨率极限是影响成像实验分辨率的主要因素.%A Schwarzschild microscope working at 13. 5 nm was developed According to the theory of a coaxial two-mirror system, the optical structure of Schwarzschild objective was designed by eliminating third-order spherical aberrations, coma and astigmatism. Experiments show that the spatial resolution of the designed objective achieves 550 lp/mm within the field of ± 0. 3 mm with respect to the calculation of modulation transfer function. Based on the working wavelength and incidence angle of lights,the Mo/Si multilayer optics with the reflectivity of 61 % at 13.5 nm was designed and fabricated. In order to remove visible and ultraviolet lights,a filter with materials of Zr, Si and S13N4 was designed and fabricated,and the transmittance of 21.1% was obtained at 13. 5 ran. With the purpose of demonstrating the resolution of microscope, the 60 lp/mm grid backlit by laser produced plasma was imaged via the Schwarzschild microscope on a Charge Coupled Device (CCD), and the results show that the imaging system can offer the resolution of 3 μm in the 0. 5 mm field. It concludes that the resolution of imaging experiment is limited by the resolution of CCD camera.