Shift-multiplexed holographic memory using the two-lambda method

Barbastathis, George; Psaltis, Demetri

doi:10.1364/ol.21.000432

Cited by 43 publications

(12 citation statements)

References 9 publications

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“…Recording and storing of information into holographic memories have in recent years received a great deal of attention [1][2][3][4] and as one of the possible base materials for these memories photopolymer systems have been extensively studied. [5][6][7] Besides storage of information, recording diffraction gratings into these photopolymer materials provides means for manipulation of light or beam shaping.…”

Section: Introductionmentioning

confidence: 99%

Real-time direct measurement of diffraction efficiency of reflection gratings in photopolymer recording materials

Vojtíšek

Květoň

2015

SPIE Proceedings

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Photopolymer recording systems have received a great deal of attention as a material for optical information storage and production of diffraction gratings. Before using these materials in such systems, it is important to characterize them and understand the processes which run during holographic recording, so that the recording itself can be optimized to obtain an efficient diffraction grating. In this contribution, we present a new method for real-time measurement of the diffraction response of reflection gratings during the recording process. Usually, the recording process in photopolymers is characterized by the real-time measurement of a transmission diffraction grating growth. This method does not allow measuring the growth of gratings with a very narrow spatial period in the reflection configuration. The new approach is based on the idea that the reflection grating is illuminated with white light at a different angle from the recording one and the diffraction efficiency is continuously measured with a spectrophotometer. Kogelnik's coupled wave theory is used as the theoretical background in this contribution. Experimentally, the photopolymer Bayfol HX has been tested in the reflection configuration and growth curves have been measured to show a good applicability of the detection method.

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Section: Introductionmentioning

confidence: 99%

Real-time direct measurement of diffraction efficiency of reflection gratings in photopolymer recording materials

Vojtíšek

Květoň

2015

SPIE Proceedings

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“…But there exists a major problem in practical application, which is the difficulty of inducing directly holographic gratins in the photorefractive crystal by using infrared or near-infrared spectral bands [3][4][5] . The effective solution is the so-called two-lamda method 6,7 , i.e., forming the holographic grating by short wavelength but reconstructing it by longer wavelength. In this case the wavelength conversion and the wave-front conversion should be considered synchronously.…”

Section: Introductionmentioning

confidence: 99%

Study of wavelength-dependent diffraction properties of photorefractive volume holographic lenses for optical beams conversion

Yan

Liu

et al. 2007

Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications

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A new type of photorefractive volume holographic lenses for converting a plane wave to a lateral-spread spherical wave with different wavelength has been suggested, which are recorded at 632.8nm wavelength and reconstructed at 800nm wavelength. Using the coupled-wave theory, the wave-front conversion by photorefractive volume holographic lenses between spherical and plane waves is studied. The off-Bragg parameter values of the holographic lenses in the reconstruction process are analyzed. The dependence of diffraction efficiencies on the focal length of recording spherical wave and the geometric sizes of the photorefractive holographic lenses are discussed in detail. In addition the intensity distributions of the diffracted beam are analyzed also.

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“…Another method is the use of periodic copying 3 . Here we consider the two lambda method, in which the reading and readout wavelengths are different [4][5][6][7][8] . The motivation for using different wavelengths of laser for recording and readout is simple: If a crystal has an absorption spectrum with a substantial variation as a function of wavelength, by recording at a wavelength λ 1 at which the crystal is highly sensitive and reading out at a second wavelength λ 2 at which the crystal is relatively insensitive, we can reduce the decay of the holograms caused by the readout illumination 8 .…”

Section: Introductionmentioning

confidence: 99%

Digital hologram reconstruction using the dual-wavelength method

Kim

2003

SPIE Proceedings

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In this paper, to reduce the Bragg-mismatch problem of the dual-wavelength method, we record the hologram in the Dupont's photopolymer of thickness L=38µm and use a digital image data which has 78×104 bit/page. Also, to compensate the image magnification problem, a pair of cylinder lens consisting of 4F system behind the F 2 lens and proposed data matrix image processing technique is used. As a result, the raw BER through Gaussian fitting after extracting binary data is around 3.09×10 -6 .

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Shift-multiplexed holographic memory using the two-lambda method

Cited by 43 publications

References 9 publications

Real-time direct measurement of diffraction efficiency of reflection gratings in photopolymer recording materials

Real-time direct measurement of diffraction efficiency of reflection gratings in photopolymer recording materials

Study of wavelength-dependent diffraction properties of photorefractive volume holographic lenses for optical beams conversion

Digital hologram reconstruction using the dual-wavelength method

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