全息照相

全息照相（Holography）是利用激光为光源，拍摄３D空间景深立体影像的技术。经曝光，显影加工处理后形成影像底片称为全息图（Hologram）。用来记录立体影像的载体即感光版称作全息照相版（Holographicplate）。全息照相是利用光的波动性及特有的干涉性和衍射来拍摄物体的，以使物体的立体影像显现出来。当用激光器输出的光束经分光镜分成两束光，其中一束光照射在被摄物体时，会在其表面反射而产生物体光。这种物体光映射在感光版上，同时另一束没有受到被摄物体影响的光（参考光）也投射到感光版上，这时感光版上就会发生光的干涉现象…     

全息照相及常用的全息记录材料

本文简要概述了全息照相的概念、白光显示全息图及其应用状况。全息照相是一种新型的照相技术,与普通照相相比较具有三维立体性、重复记录性、可分割性等优点。本文还介绍了用于全息照相的记录材料,主要有三种:卤化银全息干版、DCG干版和高分子感光材料。     

Adaptive Microwave Holography

Microwave holography differs from optical holography in three distinct ways. First, in microwave holography the reference field may be eliminated and replaced by correct phasing of the local oscillator within the microwave receiver. Second, the reference wave need not coexist in time with the signal or object field. Third, it is not necessary that the object field be measured simultaneously across the array. Aside from these fundamental differences, which give the microwave holographer additional freedom in system design, another practical difference should be noted. Because of the long wavelength used in microwave holography, the aperture must be huge to obtain images with fine resolving power. Such apertures are often mechanically unstable. By introducing adaptivity or self-cohering into the creation and measurement of the reference field, it is possible to ‘straighten out’ a distorted microwave aperture. An instrument which performs these operations is called a radio camera. A twodimensional radar map of a few blocks of a small town in Pennsylvania illustrates the process.     

Terahertz Digital Holography

Abstract: Terahertz (THz) technology is combined with digital holography for THz imaging. The characteristics of the propagation behaviour of the THz pulse in free space are investigated by using numerical simulations. The algorithm is based on the angular spectrum theory. The spatiotemporal coupling of the THz pulse during propagation results in a significant time‐dependent beam diameter and wave front. The two‐dimensional dynamic evolution of the THz pulse passing through an aperture is obtained. The diffraction is time‐dependent as the pulse travels through the object, which can be clearly observed in simulations. The simulation algorithm and result have been used to reconstruct the original object, with the spatiotemporal amplitude recorded by using a charge‐coupled device (CCD). The implementation of THz digital holography is presented and the corresponding experimental result given.     

Holography in phase space

Holography is reformulated by using the framework of phase-space optics. The Leith-Upatnieks off-axis reference hologram is compared with precursors, namely, single-sideband holography. The phase-space representation of complex amplitudes focuses on similarities between different holographic recording schemes and is particularly useful for investigating the degree of freedom and the space-bandwidth product of optical signals and systems. This allows one to include computer-generated holography and recent developments in digital holography in the discussion.     

Incoherent Soft X-ray Holography

Abstract

A long wavelength extension of coded aperture imaging is considered in the context of a possible application in soft X-ray microscopy. It is shown that zone plate coded aperture imaging extends naturally to longer wavelength applications and this is demonstrated experimentally. For a given source of incoherent radiation and exposure time, it is shown that incoherent techniques produce images with a substantially greater signal-to-noise ratio than coherent holography. Incoherent holography also has substantially reduced temporal coherence requirements. The practical implementation of the technique is briefly discussed.     

物质波全息和干涉技术的进展

近年来物质波全息技术,已取得了很大的发展,特别是电子全息术,已达到了原子分辨率的水平.本文就电了、原了和中子全息术的发展状况、原理和有关的应用作一简要介绍.     

彩色全息的进展

本文介绍真彩色全息技术的进展，包括早期的彩色全息术，白光处理彩色全息术，透射彩色彩虹全息术，彩色傅里叶变换全息术，反射彩色全息术。阐述全息图的构成与再现过程，给出了这些技术的实验例证。