Geometrical optics of holograms

2008

We review several methods of generating holograms of 3D realistic objects illuminated by incoherent white light. Using these methods, it is possible to obtain holograms with a simple digital camera, operating in regular light conditions. Thus, most disadvantages characterizing conventional holography, namely the need for a powerful, highly coherent laser and meticulous stability of the optical system are avoided. These holograms can be reconstructed optically by illuminating them with a coherent plane wave, or alternatively by using a digital reconstruction technique. In order to generate the proposed hologram, the 3D scene is captured from multiple points of view by a simple digital camera. Then, the acquired projections are digitally processed to yield the final hologram of the 3D scene. Based on this principle, we can generate Fourier, Fresnel, image or other types of holograms. To obtain certain advantages over the regular holograms, we also propose new digital holograms, such as modified Fresnel holograms and protected correlation holograms. Instead of shifting the camera mechanically to acquire a different projection of the 3D scene each time, it is possible to use a microlens array for acquiring the entire projections in a single camera shot. Alternatively, only the extreme projections can be acquired experimentally, while the middle projections are predicted digitally by using the view synthesis algorithm. The prospective goal of these methods is to facilitate the design of a simple, portable digital holographic camera which can be useful for a variety of practical applications.

Defense and Security 2008: Special Sessions on Food Safety, Visual Analytics, Resource Restricted Embedded and Sensor Networks, and 3D Imaging and Display, 2008

We review several methods of generating holograms of 3D realistic objects illuminated by incoherent white light. Using these methods, it is possible to obtain holograms with a simple digital camera, operating in regular light conditions. Thus, most disadvantages characterizing conventional holography, namely the need for a powerful, highly coherent laser and meticulous stability of the optical system are avoided. These holograms can be reconstructed optically by illuminating them with a coherent plane wave, or alternatively by using a digital reconstruction technique. In order to generate the proposed hologram, the 3D scene is captured from multiple points of view by a simple digital camera. Then, the acquired projections are digitally processed to yield the final hologram of the 3D scene. Based on this principle, we can generate Fourier, Fresnel, image or other types of holograms. To obtain certain advantages over the regular holograms, we also propose new digital holograms, such as modified Fresnel holograms and protected correlation holograms. Instead of shifting the camera mechanically to acquire a different projection of the 3D scene each time, it is possible to use a microlens array for acquiring the entire projections in a single camera shot. Alternatively, only the extreme projections can be acquired experimentally, while the middle projections are predicted digitally by using the view synthesis algorithm. The prospective goal of these methods is to facilitate the design of a simple, portable digital holographic camera which can be useful for a variety of practical applications.

2013

Nowadays, the most beautiful 3D pictures and movies are created by means of holograms. The most advantage of this technique is the possibility to observe 3D images without using glasses. The quality of created images by this method has surprised everyone. In this paper, the experimental steps of making a transmission hologram have been mentioned. In what follows, current advances of this science-art will be discussed. In another section of this paper the optical application of holography has been reviewed. Finally, the predictions for the future of holography have also been studied. .

International Journal of Computational Science and Engineering, 2015

Since its conception, holography has been put to a variety of uses including data storage, security, and interferometry. However, perhaps the most popular application of holography is using the technique to make three-dimensional images [1]. This paper describes an algorithm for computationally generating holograms along with methods to fabricate the hologram. Holography has since made a jump from optics tables to computers. The phrase, "digital holography", is common place in the optics community; it describes the methods used to reconstruct holographic images from physically recorded holograms as well as the methods used to construct holograms from virtual objects using a computer. In fact we have the ability to create digital holograms from imaginary objects and then recreate the image of those objects using the same digital holograms, the entire process performed on a single computer. Computer generated holograms printed on transparencies have also been used as optical filters.

International Journal of Electronics, 1979

The wave conversion process in a volume phase hologram, recorded by two monochromatic waves satisfying geometrical optics, is studied. Coupled wave differential equations are derived and, from the solutions given in a companion paper, numerical results are presented for plane-to-plane, plane-to-spherical and spherical-to-plane wave conversion. It is shown that in the non-paraxial case the polarization of the input wave may significantly change during transit through the hologram.

Optics Communications, 1986

A coupled wave analysis is presented to study the diffraction of light by on-axis holographic lenses. The mathematical procedure is carried through by using generalized coordinates. Analytical and numerical results are evaluated, allowing a physical interpretation in terms of waves geometry. ' Address for the Academic year 1985-86, School of Optometry, University of California, Berkeley, CA 94720, USA. 0 0304018/86/SO3.50 0 Elsevier Science Publishers B.V.

2011

Phase-only holographic projection has prompted a great deal of research and has often been cited as a desirable method of 2-D image formation, since such a technique offers a number of advantages over conventional imaging projection technology [1], [2]. Although holographic image formation was demonstrated some forty years ago [3], efforts at realizing a real-time 2-D video projection system based on this technique have not been successful, principally due to the computational complexity of calculating diffraction patterns in real time and the poor quality of the resultant images. In this paper, a new approach to hologram generation and display is presented which overcomes both of these problems, enabling—for the first time—a high-quality real-time holographic projector.

Education and Training in Optics and Photonics, 2009

Laboratory works on holograms recording, reconstruction and interpretation are useful for two reasons. Firstly, holography is widely used in science and engineering. Secondly, training labs in holography require complex applying of knowledge on interference, diffraction, coherency and other domains of optics. Educational kit and methodological instructions for optical experiments were presented in the previous paper 1 . The desktop holographic camera described in this paper is one of the additional functional units of the kit. The desktop holographic camera does not require additional protection against vibrations even if the exposure time is several minutes. This is a compact holographic installation for recording Denisyuk holograms. Two experiments are described in the paper to illustrate the usefulness of holographic laboratory works. The first one is a recording and reconstruction of a Denisyuk hologram. The second one is a recording and interpretation of a double-exposure interferogram when the holoplate is sagged due to loading between exposures. Also included in the paper are holographic setup and laboratory works on digital holography. These experiments require, in addition, complex applying of knowledge on photo receivers, CCD and other domains of photonics.

Thesis Brunel University 1991 Source Dissertation Abstracts International Volume 53 01 Section B Page 0358, 1991

Recording and reconstruction of in line holograms 2.2.1 Visibility of fringes at the center of the hologram 5 2.3.1 Computer plot of equation (2.3.3) 2.3.2 A typical HID curve 2.3.3 A typical TalE curve 2.3.4 Schematic curves showing density and transmission for an emulsion plotted against log E. 3.1.1 Recording and reconstruction geometry of recording and reconstruction process 3.1.2 Experimental arrangement Belz and Shofner's model 3.3.1 Co ordinates geometry for Extended imaging 3.3.2 Computed diffraction patterns on the hologram 3.3.3 Line scan through the center of the image 3.3.4 Contour plot of equation (3.3.19) 3.3.5 Three dimensional plot of equation (3.3.19) 3.3.6 Coordinate geometry of the possible future work 4.1.1 Schematic diagram of data acquisition system 4.1.2 Comparison of the dark current of two cameras 60 4.1.3 Comparison of the optical noise of two cameras 61 when coherently illuminated. 4.1.4 Diffraction patterns arising from a thin wire 62 4.1.5 Flow chart for the data acquisition using Asystant GPIB 67 4.1.6 Comparison of the diffraction patterns from a thin 68 wire acquired manually or using Asystant GPIB 4.1.7 Graph for the calibration of the time scale 69 4.2.1 A simple spatial filter with collimating lens 70 4.2.2 Collimating lens with a pinhole and microscopic lens 72 4.3.1 TalE curves of commonly used emulsions 74 4.4.1 Location of discs on the glass substrate 77 4.4.2 Patterns of opaque discs 77 4.4.3 Drawing of the test object holder 79 (iii) Page No. 4.5.1 Aperture placed just after the collimating lens 82 4.5.2 Aperture placed just before the recording plane 82 4.5.3 Aperture placed on the hologram in reconstruction 84 4.5.4 Repeatability of the experimental results 84 5.1.1 Theoretical plot of in focus image group C3 for 90 0=19.616 showing measurement criteria 5.1.2 Contour plots of in focus images for 0=3.832 94 5.1.3 Contour plots of images for 0=7.016 95 5.1.4 Contour plots of images for 0=10.173 96 5.1.5 Contour plots of images for 0=13.324 97 5.1.6 Contour plots of in focus images for 0=19.616 98 5.1.7 Contour plot of group C3 for 0=19.616, Q=O.O mm 99 'If (x,y) l1t 9'1 9'2 Object wave. Radial distance in the hologram plane. Radial distance in the image plane. Resolution of the hologram. Reference wave. Coherence time of the laser. Exposure time. Constant background in the reconstruction of an in-line hologram. Amplitude transmittance. Focusing parameter. Measurement between the outer most peaks of the image. Measurement of the image at 25% of its central intensity. Measurement of the image at 50% of its average intensity. Depth of the field of in-line hologram. Recording distance of the object from the hologram. Reconstruction distance of the image from the hologram. The focusing condition.