Holographic recording and retrieval of polarized light by use of polyester containing cyanoazobenzene units in the side chain

Kawano, Katsunori; Ishi‐i, Tsutomu; Minabe, Jiro; Niitsu, T.; Nishikata, Yasunari; Baba, Kazuo

doi:10.1364/ol.24.001269

Cited by 55 publications

(20 citation statements)

References 6 publications

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“…Photopolymer-based systems [10][11][12] have proven to be advantageous holographic media over photoisomerizable [13][14][15] or photorefractive systems [16] due to their superior dynamic range, photosensitivities, stability, and easy production. However, polymerization-shrinkage-induced distortion is a major hurdle for the reliable use of photopolymers, and is repeatedly referred to in the literature.…”

Section: Introductionmentioning

confidence: 99%

Low‐Distortion Holographic Data Storage Media Using Free‐Radical Ring‐Opening Polymerization

Choi

Chon

et al. 2009

Adv Funct Materials

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Holographic data storage, due to its potential to increase capacity beyond one terabyte per disk, is tipped to be one of the next generation optical data storage technologies. Polymer‐based systems are leading candidates due to their high dynamic range, high sensitivities, and flexible and easy production, and yet polymerization‐shrinkage‐induced distortion is a major hurdle for its reliable use. In this paper, a new free radical polymerization holographic recording medium, based on low shrink cyclic allylic sulfides (LS‐CASs) ring‐opening monomers, is proposed and demonstrated. The percentage of volume shrinkage is measured to be 0.02%, with refractive index (RI) contrast of (1.01 ± 0.5) × 10−3. The measured volume shrinkage is, to the authors' best knowledge, the best reported so far in the literature. Other parameters such as sensitivity, dynamic range, and dark reaction properties are also measured, where the values can be optimized with high RI functional groups without sacrificing the low shrinkage.

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Section: Introductionmentioning

confidence: 99%

Low‐Distortion Holographic Data Storage Media Using Free‐Radical Ring‐Opening Polymerization

Choi

Chon

et al. 2009

Adv Funct Materials

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“…They not only allow one to reconstruct the intensity and phase of the original object beam but also its polarization. [13] The reconstructed polarization can even be perpendicular to the polarization of the reference beam. This yields the additional possibility of largely eliminating light-scattering problems, since the polarization of the scattered light is then perpendicular to the polarization of the reconstructed image.…”

mentioning

confidence: 99%

Polymer Blends with Azobenzene‐ Containing Block Copolymers as Stable Rewritable Volume Holographic Media

et al. 2007

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Volume holography is a promising technology for high-capacity optical data storage. [1,2] When utilizing the entire volume of a medium instead of only its surface, capacities above one terabyte on a memory medium the size of a compact disc are theoretically possible. Recent developments in the field of holographic storage materials and advances in storage techniques and technology are summarized in review articles by Ashley et al. [3] and Hesselink et al. [4] Although there are still material challenges, write-once media seem to be fairly advanced. In search of rewritable media, many studies have been performed on photorefractive crystals and organic glasses. [1,4] Manufacturing single crystals of the required size is very expensive, and a major drawback of the organic photorefractive materials is the requirement of very high electric field strengths. With increasing material thickness, the voltage necessary for creating the field becomes difficult to handle. A different potential class of rewritable media are polymers containing photoaddressable azobenzene chromophores.[5] Many studies have been performed on azobenzene-containing polymer films with thicknesses in the range of 0.5-10 lm. [3,6] However, the preparation of the thick samples required for multiplexing with sufficiently low optical density remains difficult to achieve. Because the absorption coefficient depends on the wavelength, it is in principle possible to tune a laser with an adjustable wavelength (e.g., a dye laser) to the very edge of the absorption band. [7] If writing is to be performed at a wavelength where fixed-wavelength, solid-state lasers are available (515 or 532 nm), however, a concept that allows for diluting the chromophores is required. So far, the best results have been reported by Minabe et al. with a homogeneous polymer blend based on an azobenzene-containing polymer and a similar but nonabsorbing polymer. [8] In a sample of 250 lm thickness, a set of 20 data pages were successfully inscribed; yet, the individual holograms were not completely spatially overlapping. The important issues of stabilizing the inscribed data and rewritability were not addressed. We use a different concept of controlling the optical density, by using block copolymers that contain azobenzene side groups in one block. Block copolymers with less than 15 vol % of one component form spherical microphases with typical diameters in the range of 10-20 nm. Thus, we can macroscopically dilute the chromophores while, at the same time, keeping them in a local confinement. The latter is important for the stability of the inscribed information. In an earlier paper, we have already reported the formation of individual holographic gratings in 10 lm thick films of a material that contained azobenzene and nonabsorbing three-ring mesogenic side groups in the minority phase.[9] In the confined geometry, the presence of a cooperative effect of the side groups was demonstrated. The mesogenic side groups were reoriented together with the chromophores; furthermore, in materia...

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“…Polarization multiplexing has been used to improve the capacity of holographic memories by using materials that can maintain the polarization state of the recorded beam during readout. 6 Polarization encoding techniques have been used for image encryption applications [7][8][9][10][11][12] and to perform optical logic operations such as XOR and XNOR. 13 In this paper we discuss and experimentally demonstrate an optical system that can encode 2D signals (images) as distinct polarization states.…”

Section: Introductionmentioning

confidence: 99%

Polarization encoding and multiplexing of two-dimensional signals: application to image encryption

2006

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Holographic recording and retrieval of polarized light by use of polyester containing cyanoazobenzene units in the side chain

Cited by 55 publications

References 6 publications

Low‐Distortion Holographic Data Storage Media Using Free‐Radical Ring‐Opening Polymerization

Low‐Distortion Holographic Data Storage Media Using Free‐Radical Ring‐Opening Polymerization

Polymer Blends with Azobenzene‐ Containing Block Copolymers as Stable Rewritable Volume Holographic Media

Polarization encoding and multiplexing of two-dimensional signals: application to image encryption

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