&lt;title&gt;Holographic optical element for compact fingerprint imaging system&lt;/title&gt;

Metz, Michael; Coleman, Zane A.; Phillips, Nicholas J.; Flatow, Carl

doi:10.1117/12.235454

Cited by 5 publications

(3 citation statements)

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“…Photopolymers have been extensively investigated as holographic recording media for several decades − for many applications, including holographic scanners, , LCD displays, , helmet-mounted displays, optical interconnects, − waveguide couplers, holographic diffusers, − laser eye protection devices, automotive lighting, and security holograms. , Materials adequate for commercial application in archival data storage, however, have not yet been developed. Holograms (data) are stored in photopolymer materials as spatial modulations of refractive index created in response to an interference pattern generated by incident laser beams.…”

Section: Introductionmentioning

confidence: 99%

Epoxy Resin−Photopolymer Composites for Volume Holography

2000

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Efficient materials for recording volume holograms are described that could potentially find application in archival data storage. These materials are prepared by mixing photopolymerizable vinyl monomers with a liquid epoxy resin and an amine hardener. A solid matrix is formed in situ as the epoxy cures at room temperature. The unreacted vinyl monomers are subsequently photopolymerized during hologram recording. A key feature of these materials is the separation of the epoxy and vinyl polymerizations. This separation allows for a large index contrast to be developed in holograms when components are optimized. The standard material described in this work consists of a low index matrix (n = 1.46), comprised of diethylenetriamine and 1,4-butanediol diglycidyl ether, and a high index photopolymer mixture (n = 1.60) of N-vinylcarbazole and N-vinyl-2-pyrrolidinone. This material is functional in thick formats (several millimeters), which enables narrow angular bandwidth and high diffraction efficiency. A dynamic range (M/#) up to 13 has been measured in these materials. Holographic performance is highly dependent on the amount of amine hardener used, as well as on photopolymer shrinkage.

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Section: Introductionmentioning

confidence: 99%

Epoxy Resin−Photopolymer Composites for Volume Holography

2000

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“…[14,15] Photopolymer can be divided to several different types of photopolymers: dry film type [16,17], solution type [18,19], and liquid crystal (LC) composite type. [20][21][22][23][24] Among those, dry film photopolymers have many advantages of low cost, simple process, good sensitivity and can be easily produced at large scale.…”

Section: Introductionmentioning

confidence: 99%

Holographic security media prepared from photochromic fluorescent films

Kim

2008

Optical Materials in Defence Systems Technology V

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Holographic recording using a multi-functional photopolymer was explored for securities and anticounterfeit. The preparation of photofunctional photopolymer film was based on monomers and photochromic fluorescent material, which provides information recording and security of the information, respectively. The content of the monomer and photochromophore for such photopolymer film was optimized to give high diffraction efficiency and high photochromic contrast. A highly secure recording and reading method was suggested for the recorded information, based on diffraction, color and fluorescence change.

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“…Using the diagram in Figure 1 we can deduce the equations for the reference and signal waves. AsemY_t) and Are lkmX sine +-cose (1) These functions represent the signal and reference waves respectively with A and Ar as the signal and reference amplitudes, a the absorption coefficient, km the wave propagation constant in the medium, and e the angle of the reference beam from the surface normal inside the film. The total amplitude at any point in the hologram is thus ikmx sin8 A0 = Asem_3t) + Are cose and the intensity is expressed as (2) 2ay I = A0 x Atot* = Ae_2 y+t) + Aec05e + 2As Are We now wish to find the average contrast (C) = JC dy.…”

Section: Introductionmentioning

confidence: 99%

<title>Holograms in the extreme edge-illumination geometry</title>

Coleman

Metz²,

Phillips

1996

SPIE Proceedings

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The recording of holograms in which the reference beam enters through the supporting substrate involves attenuation factors which differ strongly between signal and reference. This paper addresses the issue of fringe contrast under these extreme conditions and provides quantitative data that are indicative of at least a partial solution to the problem. We define a spatial average for the fringe contrast and offer results which follow our theoretical model for Du Pont OnmiDexTM photopolymers. The direct edge referenced technique for recording is re-visited with observation of a new phenomenon which we call self-induced index matching. An alternative fringe recording geometry is proposed and compared with direct recording.

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<title>Holographic optical element for compact fingerprint imaging system</title>

Cited by 5 publications

References 0 publications

Epoxy Resin−Photopolymer Composites for Volume Holography

Epoxy Resin−Photopolymer Composites for Volume Holography

Holographic security media prepared from photochromic fluorescent films

<title>Holograms in the extreme edge-illumination geometry</title>

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