Dynamisches System für die Aufnahme und optische Rekonstruktion von Hologrammen

Author(s): Günther Wernicke, Johannes Frank, Christian Günther, Sven Krüger

Abstract:

“Adressierbare räumliche Lichtmodulatoren mit einer möglichst idealen Phasenmodulation sind die Voraussetzung für deren Anwendung in der digitalen Holographie. Eine angepasste Treiberelektronik und eine genaue Kenntnis des Modulationsverhaltens kann zu einem dynamischen Phasenmodulations-System mit nahezu linearer Kennlinie und einem maximalen Phasenhub von 2 pi führen.
Ein System zur Aufnahme und Rekonstruktion von digitalen Hologrammen mit digitaler Bearbeitung der Hologrammdaten wird gezeigt. Daten von einer CCD-Kamera werden in den PC eingelesen und von diesem auf den Lichtmodulator gegeben. Damit wird ein Analog-Digital-Konverter (Hologrammaufnahme) und ein Digital-Analog-Konverter (optische Hologrammrekonstruktion) realisiert. Das Auflösungsvermögen wird diskutiert und Anwendungsmöglichkeiten, insbesondere durch Manipulationen am rekonstruierten Wellenfeld werden gezeigt.
Damit werden neue Anwendungen in der zerstörungsfreien holographischen Prüfung und in der holographischen Mikroskopie und der Kombination von beiden möglich. ”

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Publication: DGaO-Proceedings 2006
Issue/Year: DGaO-Proceedings 2006, 107. Tagung, Vortrag: B36,
ISSN: 1614-8436

Applications of the high-resolution optical reconstruction of digital holograms

Author(s): Günther Wernicke, Johannes Frank, Hartmut Gruber, Matthias Dürr, Andreas Langner, Stefan Eisebitt, Christian Günther, Larbi Bouamama, Sven Krüger and Andreas Hermerschmidt

Abstract:

“Adressable spatial light modulators with as much as possible ideal phase modulation are the precondition for their application in digital holography. An adapted driver electronics for the modulator and a correct knowledge of the modulation behavior can lead to a dynamic phase modulating device with nearly linear characteristic curve and a maximum phase range of 2pi. We show a system for recording and reconstruction of digital holograms applying a spatial light modulator for the optical reconstruction and the digital processing of the holograms. The data of a CCD-camera are taken to a PC and sent to a spatial light modulator. In that sense we realised an analog-digital converter for recording and a digital-analog converter for the optical hologram reconstruction. We discuss the resolution of the reconstruction and their applications, especially possibilities for the manipulation with the reconstructed wave field. ”

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Publication: SPIE Proceedings
Issue/Year: Proc. SPIE, Vol. 6136, 61360Q (2006)
DOI: 10.1117/12.651622

Optimally tuned spatial light modulators for digital holography

Author(s): Christian Kohler, Xavier Schwab, and Wolfgang Osten

Abstract

“Digital holography and comparative digital holography are applications that require computer-addressable modulators for the optical reconstruction of digital holograms. The quality of the reconstructed holograms depends on the modulator’s properties. Therefore a characterization of the modulators is required. We show the result of a modulator characterization and the modulator’s influence on the quality of the reconstructed hologram. We then compare qualitatively and quantitatively the optical reconstruction of phase and amplitude holograms by considering their level of detail and their diffraction efficiency.”

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Publication: Applied Optics
Issue/Year: Applied Optics, Vol. 45, Issue 5, pp. 960-967 (2006)
DOI: 10.1364/AO.45.000960

Accurate encoding of arbitrary complex fields with amplitude-only liquid crystal spatial light modulators

Author(s): Victor Arrizón, Guadalupe Méndez, and David Sánchez-de-La-Llave

Abstract:

“We show that computer generated holograms, implemented with amplitude-only liquid crystal spatial light modulators, allow the synthesis of fully complex fields with high accuracy. Our main discussion considers modified amplitude holograms whose transmittance is obtained by adding an appropriate bias function to the real cosine computer hologram of the encoded signal. We first propose a bias function, given by a soft envelope of the signal modulus, which is appropriate for perfect amplitude modulators. We also consider a second bias term, given by a constant function, which results appropriate for modulators whose amplitude transmittance is coupled with a linear phase modulation. The influence of the finite pixel size of the spatial light modulator is compensated by digital pre-filtering of the encoded complex signal. The performance of the discussed amplitude CGHs is illustrated by means of numerical simulations and the experimental synthesis of high order Bessel beams.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 13, Issue 20, pp. 7913-7927, 2005
DOI: 10.1364/OPEX.13.007913

Encoding fully-complex transmittance with coupled amplitude-phase liquid-crystal modulator

Author(s): Victor M. Arrizón, Luis A. Gonzalez Lopez

Abstract:

“We propose a holographic code for synthesis of fully-complex transmittance, which can be implemented employing a twisted-nematic liquid-crystal display, two linear polarizers, and a He-Ne laser. This simple setup provides a reduced phase range and amplitude modulation with significant variance. Our holographic code efficiently exploits this constrained modulation for the accurate encoding of arbitrary complex transmittance. Two experimental examples illustrate the good performance of the holographic code.”

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Publication: SPIE – Optical Engineering
Issue/Year: Opt. Eng., Vol. 44, 070502 (2005)
DOI: 10.1117/1.1978427

Computer-generated holograms with optimum bandwidths obtained with twisted-nematic liquid-crystal displays

Author(s): Victor Arrizón, Luis A. González, Rodrigo Ponce, and Alfonso Serrano-Heredia

Abstract:

“We discuss a computer-generated hologram for encoding arbitrary complex modulation based on a commercial twisted-nematic liquid-crystal display. This hologram is implemented with the constrained complex modulation provided by the display in a phase-mostly configuration. The hologram structure and transmittance are determined to obtain on-axis signal reconstruction, maximum bandwidth, optimum efficiency, and high signal-to-noise ratio. We employed the proposed holographic code for the experimental synthesis of first-order Bessel beams.”

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Publication: Applied Optics
Issue/Year: Applied Optics, Vol. 44, Issue 9, pp. 1625-1634, 2005
DOI: 10.1364/AO.44.001625

A single-stage reconfigurable 2-D optical perfect-shuffle network system using multiplexed phase holograms

Author(s): Kyongsik Choi Byoungho Lee

Abstract:

“We propose a single-stage reconfigurable two-dimensional (2-D) optical perfect-shuffle network system (PSNS) using multiplexed phase holograms on one phase-type spatial light modulator (SLM). Phase holograms are used that adopt dynamically combined and multiplexed holograms to implement 2-D perfect shuffling of optical images. Experimentally, we demonstrate the proof-of-principle of the proposed single-stage reconfigurable 2-D optical PSNS using a collimated light source, the multiplexed phase holograms on a phase-type SLM, and a Fourier transform lens.”

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Publication: IEEE, Photonics Technology Letters
Issue/Year: IEEE, Photonics Technology Letter, Volume: 17, Issue: 3 pp. 687-689 (2005)
DOI: 10.1109/LPT.2004.842327

Full-color autostereoscopic 3D display system using color-dispersion-compensated synthetic phase holograms

Author(s): Kyongsik Choi, Hwi Kim, and Byoungho Lee

Abstract:

“A novel full-color autostereoscopic three-dimensional (3D) display system has been developed using color-dispersion-compensated (CDC) synthetic phase holograms (SPHs) on a phase-type spatial light modulator. To design the CDC phase holograms, we used a modified iterative Fourier transform algorithm with scaling constants and phase quantization level constraints. We obtained a high diffraction efficiency (~90.04%), a large signal-to-noise ratio (~9.57dB), and a low reconstruction error (~0.0011) from our simulation results. Each optimized phase hologram was synthesized with each CDC directional hologram for red, green, and blue wavelengths for full-color autostereoscopic 3D display. The CDC SPHs were composed and modulated by only one phase-type spatial light modulator. We have demonstrated experimentally that the designed CDC SPHs are able to generate full-color autostereoscopic 3D images and video frames very well, without any use of glasses.”

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Publication: Optics Express
Issue/Year: Optics Express, Vol. 12, Issue 21, pp. 5229-5236, 2004
DOI: 10.1364/OPEX.12.005229

Real time opto-digital holographic microscopy (RTODHM)

Author(s): Larbi Bouamama, Mohamed Bouafia, Guenther Wernicke, Sven Krueger and Hartmut Gruber

Abstract:

“The high development of numerical image and signal processing techniques, may lead to the replacement of conventional photosensitive media used in holography by CCD sensors: hence, to the field of digital holography. The hologram is saved in the host memory of a computer and can be reconstructed on the same place or elsewhere in a numerical manner. The development of liquid crystal displays (LCD) directly addressed by computer permits to think of opto-digital holography. The observation of the reconstructed image at a limited distance is possible when using adequate optical components, which makes not only the possibility to observe the image at a defined distance but also to control its magnification (opto-digital holographic microscopy). Since it is possible to control all experimental steps by adequate software, it is then possible to make real time opto-digital holographic microscopy. In this work, we show the experimental set-up and the obtained results, showing that this technique can be used to study different kinds of materials, connected to different conventional microscopes and to make holographic interferometry.”

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Publication:Catalysis Today
Issue/Year: Catalysis Today, Volume 89, Issue 3, 30 March 2004, Pages 337-341, 2004
DOI: 10.1016/j.cattod.2003.12.017

Complex modulation with a twisted-nematic liquid-crystal spatial light modulator: double-pixel approach

Author(s): Victor Arrizón

Abstract:

“I modify the double-phase holographic code to implement complex modulation with a transmission twisted-nematic liquid-crystal display. This device is employed in the mostly phase configuration, for which the phase modulation is coupled with a nonconstant amplitude modulation. The modified double-phase code implements arbitrary complex modulation employing the constrained complex modulation of the display.”

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Publication: Optics Letters
Issue/Year: Optics Letters, Vol. 28, Issue 15, pp. 1359-1361, 2003
DOI: 10.1364/OL.28.001359
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