Design method of high-numerical-aperture short-focal-length step phase position type thick FZP

Abstract

The invention relates to a design method of a high-numerical-aperture short-focal-length step phase position type thick FZP. The step phase position type FZP is equivalent to multiple diffraction screens based on a multi-screen diffraction theory, the diffraction effect in a step phase position type FZP body is considered, a diffraction field of the whole FZP is formed by superposing diffraction fields of multiple equivalent diffraction fields, a vector diffraction theoretical formula is formed, the step phase position type FZP can be designed and diffraction field distribution can be analyzed according to a vector diffraction theory. By adopting the design method, a computing result can be basically consistent to a time domain finite difference simulated result, and the high-numerical-aperture short-focal-length step phase position type thick FZP can be simply and effectively designed.

Description

technical field [0001] The invention relates to the field of optical microscopy and imaging technology, especially in the design of binary optical diffraction focusing elements with high numerical aperture and short focal length, and proposes to design a high-resolution short-focus multi-step phase thick Fresnel based on vector diffraction theory. The zone plate method. Background technique [0002] Focusing elements are commonly used optical elements in optical instruments and equipment. A lens is a commonly used focusing element by refraction, but it cannot be used in the X-ray band because general materials do not refract X-rays. Fresnel Zone Plate (FZP, Fresnel Zone Plate) is an important diffractive optical element, which has a wide range of applications, and can be focused by FZP from visible light to X-ray bands. On the other hand, in order to obtain high resolution, it is necessary to make a high numerical aperture lens, which is currently more difficult, because w...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the deficiency that the conventional single-screen diffraction theory cannot consider the diffraction effect in the FZP body in the design and analysis of the step phase thick FZP, propose a multi-screen diffraction theory, consider the diffraction effect in the FZP body, and provide a A Simple and Practical Method for Designing and Analyzing High-Resolution, Short-Focal-Length Step-Phase Type Thick FZPs

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