Holography is usually considered as the ultimate way to visually reproduce a three-dimensional scene. Computer-generated holography constitutes an important branch of holography, which enables visualization of artificially generated scenes as well as real three-dimensional scenes recorded under white-light illumination. In this article, we present a comprehensive survey of methods for synthesis of computer-generated holograms, classifying them into two broad categories: wavefront-based methods and ray-based methods. We examine their modern implementations in terms of the quality of reconstruction and computational efficiency. As it is an integral part of computer-generated holography, we devote a special section to speckle suppression, which is also discussed under two categories following the classification of underlying computer-generated hologram methods.

Correlation-based pointwise processing of dynamic speckle patterns is proposed for spatial characterization of activity in a sample. The result is a set of 2D activity maps of the estimates of temporal correlation, or structure functions, at increasing time lags. Pointwise computation provides spatial resolution, limited by the pixel period of the optical sensor used for acquisition of the speckle patterns. Pointwise normalization of the estimates solves the problem with the nonuniform illumination and varying reflectivity across the sample. The high contrast detailed activity maps obtained from processing of synthetic and experimental speckle patterns confirms efficiency of the proposed approach.

We employ two approaches to tune the properties of concurrently inscribed volume polarization and surface relief gratings in nanocomposite thin films containing the azopolymer PAZO (poly[1-4-(3-carboxy-4-hydrophenylazo)benzensulfonamido]-1,2-ethanediyl, sodium salt]) and goethite (α-FeOOH) nanorods. The first one is applied on the stage of sample preparation by varying the concentration of the goethite nanorods from 0% to 15%. Then, different angles between the recording beams are set in the holographic scheme, which allow us to obtain gratings with spatial periods in the range from 0.86 to 2.51 µm. Surface relief modulation close to 300 nm is achieved as well as total diffraction efficiency in the ±1 diffracted orders of more than 50%. The influence of the incorporated goethite nanorods on the properties of both volume birefringence and the surface relief grating are discussed.

A circular holographic display that consists of phase-only spatial light modulators is used to reconstruct images in visible light from digital holograms recorded under infrared (10.6 μm) illumination. The reconstruction yields a holographic digital video display of a three-dimensional ghostlike image of an object floating in space where observers can move and rotate around it.

During polarization holographic recording in azopolymer thin films, usually together with the volume anisotropic grating, a surface relief grating (SRG) is also formed. By using two consecutive exposures, it is possible to obtain a two-dimensional (2D) grating. To the best of our knowledge, the polarization properties of such gratings have not been studied yet. To determine the influence of the surface relief on the polarization selectivity of the 2D gratings, we propose two methods to suppress the SRG formation: by varying the recording conditions or varying the sample structure. In these experiments we have used the commercially available azopolymer PAZO, poly[1-4-(3-carboxy-4-hydrophenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] to perform the polarization holographic recording using a 442 nm He-Cd laser. As indicated by our results, when the surface relief is present, it strongly dominates the response of the 2D grating and it behaves almost as a scalar polarization insensitive grating. Conversely, when the SRG formation is suppressed, the polarization properties of the 2D grating in all four diffracted orders are very well pronounced. In this way, we demonstrate that we can easily control SRG formation and, if desired, obtain 2D grating with high surface relief modulation, or alternatively record polarization-selective 2D gratings with virtually no surface relief.

Statistical processing of speckle data enables observation of the speed of processes. In intensity-based pointwise dynamic speckle analysis, a map related to speed’s spatial distribution is extracted from a sequence of speckle patterns formed on an object under coherent light. Monitoring of time evolution of a process needs storage, transfer, and processing of a large number of images. We have proposed lossy compression of these images using JPEG and JPEG2000 formats. We have compared the maps computed from noncompressed and decompressed synthetic and experimental images, and we have proven that both compression formats can be applied in the dynamic speckle analysis.