基于数字显微全息技术的相位光栅结构测量

以相位光栅为实验对象,开展了基于数字显微全息技术的相位物体三维显微结构信息的再现研究.在Mach-Zender透射式实验系统的基础上,分别采用显微物镜和无透镜放大方式,对相位光栅进行放大,以提高系统横向分辨率.在显微物镜放大系统中,菲涅耳近似数值再现算法与双波长技术相结合,抑制主要系统噪音,获得相位光栅的显微结构三维分布.在无透镜放大数字显微全息系统中,分别利用菲涅耳近似法和卷积方法再现原始物波前,并提出相减法消除系统主要球面误差,获得相位光栅的深度信息.实验结果与Veeco干涉仪测试结果比对表明,光栅周期和深度结构与干涉仪测试数据相符.

Micro-structure Measurement of Phase Grating Based on Digital Micro-holography

The reconstruction research on 3D micro-structure of the phase grating via Digital Micro-Holography (DMH) was presented.In order to improve the lateral resolution based on the Mach-Zender interference system,two modes,with Micro-Objective (MO) magnification mode and with lens-less one,were proposed for magnifying the specimen.In DMH experiment with MO magnification mode,the 3D micro-structure distribution was obtained by combining Fresnel approximation approach and dual-wavelength technique to suppress the main phase aberration.For lensless magnification mode,the subtraction method was presented to eliminate the system total aberration to get the 3D phase information of the phase gating by using Fresnel approximation approach and the convolution approach,respectively.The experimental results were compared with the measurement results provided by Veeco interferometer,the parameters,such as the period and the height structure,of the phase gating were same and then the experiment in this paper was verified.The experimental conclusions were given.