软X射线Bragg-Fresnel二维聚焦镜的设计理论和方法

Design of a 2 D Focusing Bragg Fresnel Lens Used in the Soft X Ray Region

Ｘ射线Ｂｒａｇｇ－Ｆｒｅｓｎｅｌ元件是近十年发展起来的一种用于Ｘ射线波段的新型光学元件。本文介绍一种具有二维聚焦效能的Ｂｒａｇｇ－Ｆｒｅｓｎｅｌ元件的设计理论和方法。设计中采用衍射理论并用Ｃ语言编制计算机程序系统对衍射图形进行设计。对于使用波长１３．８ｎｍ，入射角５°，使用焦距２００ｍｍ的使用条件，设计结果为３５Ｍｏ／Ｓｉ双层多层膜，周期厚度７．１４ｎｍ，理论反射率约为６０％；衍射图形共４００个环带，最内环半宽度５２．５μｍ，最外环宽度１．３μｍ。

X rag Bragg Fresnel optics is a new X ray region optical element developed recently. This paper introduces a kind of designing theory and method using at 2 D focusing Bragg Fresnel lens. A set of computer program for diffraction pattern is described in this paper. Our 2 D focusing Bragg Fresnel lens consists of 35 bilayers multilayer and doublelayer thickness of 7.14nm, and the diffraction pattern has such parameters of 400 zones, inner zone half width 52.5μm and outer zone width 1.3μm.