Pavez C, Pedreros J, Avaria G, Bora B, Moreno J, Soto L
Comisión Chilena de Energía Nuclear, CCHEN, Casilla 188-D, Santiago, Chile.
Center for Research and Applications in Plasma Physics and Pulsed Power, P4, Santiago-Curicó, Chile.
Rev Sci Instrum. 2018 Dec;89(12):123103. doi: 10.1063/1.5023388.
This study presents an optical assembly and digital reconstruction method that is based on digital holography for characterizing transparent objects. The image-plane optical setup is based on a versatile Mach-Zehnder interferometer for the formation of controlled parallel fringe patterns, of tens micrometers of separations or less. The numerical reconstruction of the propagated wavefront by the hologram is performed by the Fresnel-Kirchhoff transform, and it is used of three ways: (a) interferometric phase reconstruction (as in interferometry) in the phase object position, (b) reconstruction of the wavefront amplitude at a determined distance from the object (shadowgraph technique), and (c) a composed digital reconstruction process of the wavefront amplitude, defined by a digital optical assembly for the selection of angular deflections produced by the phase object (schlieren technique). The resolving power of holographic reconstruction methodology proposed is determined by the sensitivity of hologram for detecting the interferometric phase. The fringe pattern of the hologram defines a minimum phase shift resolution of 0.15π rad. The scope of the technique is experimentally tested for a steady-state phase object.
本研究提出了一种基于数字全息术的光学组件和数字重建方法，用于表征透明物体。像平面光学装置基于通用的马赫-曾德尔干涉仪，用于形成间距为数十微米或更小的可控平行条纹图案。通过菲涅耳-基尔霍夫变换对全息图传播的波前进行数值重建，并以三种方式使用：(a) 在相位物体位置进行干涉相位重建（如在干涉测量中），(b) 在距物体确定距离处重建波前振幅（阴影图技术），以及(c) 由数字光学组件定义的波前振幅的复合数字重建过程，用于选择由相位物体产生的角偏转（纹影技术）。所提出的全息重建方法的分辨率由全息图检测干涉相位的灵敏度决定。全息图的条纹图案定义了0.15π rad的最小相移分辨率。该技术的范围针对稳态相位物体进行了实验测试。
