Micro-Holographic Multi-Layer Optical Disk Data Storage

McLeod, Robert R.; Daiber, A. J.; McDonald, M.; Sochava, Sergei L.; Robertson, T. L.; Slagle, Timothy M.; Hesselink, Lambertus

doi:10.1364/isom_ods.2005.mb3

Cited by 6 publications

(12 citation statements)

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“…10(e). The red pulse energy of 80 μJ is significantly higher than counterpropagating microhologram storage demonstrated in this same material [8], which achieved roughly 1 nJ exposure energies in the green; however, continued optimization of the red sensitizer could presumably narrow this gap considerably.…”

Section: Erasure Via Linear Photopolymerization With a Dpss Lasermentioning

confidence: 71%

“…0003-6935/08/142696-12$15.00/0 © 2008 Optical Society of America One approach is to write smooth index features at the focus of a single objective lens and then detect their presence via refractive deviation of the transmitted beam using a pick-up head on the opposite side of the disk [6]. Alternatively, two opposing heads can be used during writing to record a microhologram at the focus of the counterpropagating beams [7,8]. This micron-scale Bragg grating can then be efficiently detected in reflection.…”

Section: Introductionmentioning

confidence: 99%

“…The readout signal strength in multilayer data storage is also significantly smaller than with a traditional optical disk system. In any approach using linear recording, unintended writing by the portions of the beam out of the focus consume all but 1=M of the material dynamic range for M total layers, causing the read signal to drop as the number of layers squared [8]. This scaling strongly limits the total disk capacity.…”

Section: Introductionmentioning

confidence: 99%

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Three-dimensional optical disk data storage via the localized alteration of a format hologram

McLeod

Daiber²,

Honda

et al. 2008

Appl. Opt.

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Three-dimensional optical data storage is demonstrated in an initially homogenous volume by first recording a reflection grating in a holographic photopolymer. This causes the entire volume to be weakly reflecting to a confocal read/write head. Superposition of two or three such gratings with slightly different k-vectors creates a track and layer structure that specialized servo detection optics can use to lock the focus to these deeply-buried tracks. Writing is accomplished by locally modifying the reflectivity of the preexisting hologram. This modification can take the form of ablation, inelastic deformation via heating at the focus, or erasure via linear or two-photon continued polymerization in the previously unexposed fringes of the hologram. Storage by each method is demonstrated with up to eight data layers separated by as little as 12 microns.

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Section: Erasure Via Linear Photopolymerization With a Dpss Lasermentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Three-dimensional optical disk data storage via the localized alteration of a format hologram

McLeod

Daiber²,

Honda

et al. 2008

Appl. Opt.

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“…Similarly, in micro-holographic bit-wise volume data storage [5], diffraction efficiency decreases as the focus of the read head is offset in any direction from the bit. While this provides some measure of the size of the feature via the spatial overlap of the optical intensity and the index profile, Bragg matching also impacts the spatial dependence of efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…Direct-write lithography with a focused beam [8] or bit-wise data storage via index "bumps" [11] would thus occupy an identical region, while adding a counter-propagating beam to write micro-holograms [5,12] simply shifts the pattern in Fourier space via the carrier frequency to k z = ± 2k. The discussion can thus be easily generalized to other applications.…”

Section: Introductionmentioning

confidence: 99%

Phase and absorption metrology for thick photopolymer devices

2006

Self Cite

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Studies of development kinetics in volume photopolymers typically use transmission holography to quantify the index distribution. This method has advantages including simplicity, quantitative index data and natural mapping onto theories using harmonic expansion of the material response. A particular disadvantage is that the low spatialfrequency response corresponding to the intensity of the writing beams can never be Bragg matched and thus remains invisible.In configurations where the exposure is not primarily sinusoidal, the holographic method is not applicable. Important examples include bit-oriented data storage, direct-write lithography, and the object beam of page-based holography. In these cases the exposure intensity is essentially arbitrary and there is a need for metrology tools that can quantitatively measure the real and imaginary parts of the weak 3D index perturbation. Images produced by bright-field and phase-contrast microscopes are generally not quantitative and are corrupted by objects out of the focal plane.We have developed two methods, a form of optical diffraction tomography and a scanning transmission microscope, that are specifically designed to measure the 3D index response of holographic materials. Both are optimized to measure the extremely weak absorption and phase structures typical of photopolymers and have passbands that match the expected spatial frequencies.

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