电子学全息术用于三维物场分层再现的实验实现

On Improving Implementation of Layered Reconstruction of 3D Field by Digital Holography

基于电子学全息术 (又称数字全息术 )记录和再现光学全息图的原理和方法 ,设计了一种适合于用尺寸较小的 CCD靶面直接记录光学全息图的实验光路 ,并由此实现了三维物场清晰的分层再现。讨论了物场频谱的有效分离及提取方法 ,并提出了利用双参考光原理改善全息图再现像空间频谱带宽的新思路。与传统的光学全息术相比 ,电子学全息术借助于高分辨率 CCD记录及高速计算机数字处理技术 ,可以实现光学全息图的数字化记录和重现。同时在不改变光路的前提下 ,可以较高的重复频率完成光学全息图的记录 ,以便于记录三维物场的变化过程 ,并且可以接近实时地再现物场或对物场进行逐层分析 ,因而是一种准实时的新型全息成像技术。

Although much research has been done on implementing layered reconstruction of 3D (three dimensional) field by digital holography, we deem that certain improvements can still be made. In order to explain our improvements, section 1 reviews very briefly the principles of electronic recording and reconstruction of an optical hologram. Section 2 gives our design in some detail of an experimental setup to record the optical hologram of 3D field directly on the small photosensitive chips of a CCD (charge coupled device) array, thus obtaining a series of layered reconstructions of a 3D field, such as shown in Fig. 5. Section 4 discusses some effective ways for completely separating and intercepting the spatial spectrum of an object; this section also proposes a new way for improving the bandwidth of the spatial spectrum of a holographic reconstruction by double reference beams. We are confident that digital holography, including our improved method, can be used for effectively measuring the dynamic changes of a 3D field in real time.