光学 精密工程, 2011, 19 (8): 1709, 网络出版: 2011-08-29
13.5 nm Schwarzschild显微镜系统及成像实验
13.5 nm Schwarzschild microscope and imaging experiment
成像系统 Schwarzschild 成像显微镜 Mo/Si多层膜 滤波片 空间分辨率 imaging system Schwarzschild imaging microscope Mo/Si multilayer filter spatial resolution
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±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Si3N4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3 μm, 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。
Abstract
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 Si3N4 was designed and fabricated,and the transmittance of 21.1% was obtained at 13.5 nm. 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.
王新, 穆宝忠, 黄怡, 朱京涛, 王占山, 贺鹏飞. 13.5 nm Schwarzschild显微镜系统及成像实验[J]. 光学 精密工程, 2011, 19(8): 1709. WANG Xin, MU Bao-zhong, HUANG Yi, ZHU Jing-tao, WANG Zhan-shan, He Peng-fei. 13.5 nm Schwarzschild microscope and imaging experiment[J]. Optics and Precision Engineering, 2011, 19(8): 1709.