Angular selectivity asymmetry of holograms recorded in near infrared sensitive liquid crystal photopolymerizable materials

Harbour, Steven; Galstian, Tigran; Akopyan, R. S.; Galstyan, Artur V.

doi:10.1016/j.optcom.2004.05.009

Cited by 14 publications

(3 citation statements)

References 20 publications

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“…If the grating is read out using the Bragg condition, i.e., θ = 0, then ξ = 0 and equation ( 4) simplifies to η = sin 2 ν. In order to determine the angle selectivity, we monitored the diffracted power as a function of the read out angle [30,31]. A typical experimental angular diffraction efficiency response is presented in figure 5, which also shows the theoretically predicted response, calculated according to equation (4).…”

Section: Angular Selectivitymentioning

confidence: 97%

Transmission holographic gratings produced using networked polyurethane acrylates with various functionalities

Park

Kim

2006

Nanotechnology

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Holographic gratings have been fabricated in networked polyurethane acrylates with various cross-linking densities. It was found that low (f = 2) and high (f = 6) functionality monomers gave narrow and clean polymer–liquid crystal (LC) phase separation due presumably to the insufficient migration of LC molecules out of the polymer domains. However, the mechanisms leading to poor phase separation seem different, i.e., reaction at a slow rate for f = 2, and entrapment of LC molecules within highly networked polymer for f = 6. With intermediate monomer functionality (f = 3), relatively large channels with large LC droplets gave the greatest diffraction due to a large difference in refractive index between polymer and LC phases.

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Section: Angular Selectivitymentioning

confidence: 97%

Transmission holographic gratings produced using networked polyurethane acrylates with various functionalities

Park

Kim

2006

Nanotechnology

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“…For 1D HPDLC gratings it is generally found that n(r) exhibits a strong preferential alignment along the grating vector K g . As a result, optical diffraction from these gratings strongly depends on the polarization state of the incident beam [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. In contrast to 1D gratings, the structure of n(r) in 2D and 3D HPDLC lattices is practically unknown [26][27][28][29][30][31][32][33][34][35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional photonic lattices in polymer-dispersed liquid crystal composites

Devetak

Milavec

Rupp

et al. 2009

J. Opt. A: Pure Appl. Opt.

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The relationship between liquid crystal orientational ordering and optical diffraction properties is investigated for a two-dimensional square photonic lattice fabricated in a polymer-dispersed liquid crystal (PDLC) composite. Modifications of the nematic director field in the liquid crystal domains were induced by an external applied voltage and by heating over the nematic-isotropic (N-I) phase transition. They were studied by optical polarization microscopy and by analysing far-field optical diffraction patterns. The intensities of various diffraction orders (from the zeroth up to the eighth diffraction order) were monitored with a CCD camera, and their variations were correlated with the modifications of the director field.

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“…The efficiency and polarization of diffracted light have been found phenomenologically to depend strongly on photopolymerization conditions such as temperature and laser polarization. [24][25][26][27][28][29][30][31][32] As indicated in previous reports, an obvious increase in the ratio ( p = s ) of diffraction efficiency in polarization parallel to the grating vector to that in polarization perpendicular to the grating vector is affected by photopolymerization temperature. 31,32) Recently, photopolymerization processes at different temperatures have been investigated by monitoring diffraction changes, and the diffraction anisotropy has been discussed on the basis of the relationship between the refractive index modulation and configuration of LC droplets.…”

Section: Introductionmentioning

confidence: 95%

Diffraction Properties of Anisotropic Volume Gratings Formed in Polymer-Dispersed Liquid Crystal

Ogiwara¹,

Minato²,

Horiguchi³

et al. 2008

jjap

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Numerous theoretical and experimental investigations are being carried out on Cu-based alloys due to their technologically important shape memory properties and pseudo-elasticity, which are intimately associated with the martensitic transformation. The austenite phase in Cu-based shape memory alloys is known for its high elastic anisotropy. The complete set of second-order elastic constants (SOECs) and third-order elastic constants (TOECs) of Cu-Al-Ni in the β phase has been obtained. A combination of the deformation theory and finite strain elasticity theory has been employed to get the expressions for the strain energy density of the lattice. The theory is based on the Keating's approach by taking into account the two-body as well as three-body interactions up to second nearest neighbors in the Cu-Al-Ni lattice. The elastic constants are compared with the reported experimental values. The relevant role of the comparatively large TOECs in describing the instability of the bcc structure towards the martensitic transformation is also discussed. The aggregate elastic properties, such as the adiabatic bulk modulus, shear modulus, Cauchy pressure and anisotropy factor, are calculated. The mode Gruneisen parameters of the acoustic waves are determined based on the quasi-harmonic approximation method. The low-temperature limit of the lattice thermal expansion and the Anderson-Gruneisen parameter of Cu-Al-Ni are also obtained.

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Angular selectivity asymmetry of holograms recorded in near infrared sensitive liquid crystal photopolymerizable materials

Cited by 14 publications

References 20 publications

Transmission holographic gratings produced using networked polyurethane acrylates with various functionalities

Transmission holographic gratings produced using networked polyurethane acrylates with various functionalities

Two-dimensional photonic lattices in polymer-dispersed liquid crystal composites

Diffraction Properties of Anisotropic Volume Gratings Formed in Polymer-Dispersed Liquid Crystal

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