应用反射型球面菲涅耳波带片的成像物镜设计

Design of Objective Lens with Reflective Spherical Fresnel Zone Plate

设计了一种应用球面菲涅耳波带反射面与非球面反射面结合的成像物镜。对球面结构的菲涅耳波带反射面进行分析,推导了球面菲涅耳波带反射面近似替代非球面的方法,采用单片球面菲涅耳波带反射面和三片非球面反射面设计成像物镜,在放大倍数100×、视场角120°、菲涅耳数2.5情况下,调制传递函数在放大成像侧可实现0.6 lp/mm的40%以上,畸变小于2.2%。该设计方法为菲涅耳波带片应用于可见光成像提供了参考,并随着菲涅耳器件加工技术的不断发展具有良好的应用前景。

An objective lens composed of a spherical Fresnel zone plate mirror and aspheric mirrors is designed. The Fresnel zone plate with spherical shape is analyzed, and the method to replace aspherical mirror with spherical Fresnel zone plate approximately is deduced. The objective lens is designed with a single spherical Fresnel zone plate mirror and three aspherical mirrors. Under the condition of magnification 100, Fresnel number 2.5 and field angle 120°, the modulation transfer function reaches above 40% at 0.6 line pairs/mm on the magnification side, and the distortion is less than 2.2 %. This method can provide reference for application of Fresnel zone plate in visible light imaging, and possesses a bright future with the continuous development of fabrication technique of Fresnel devices.