| Electro-Optic Properties of Holographically Patterned, Polymer Stabilized Cholesteric Liquid Crystals (Preprint) |
JAN 2007 |
28 pages |
| Authors:
Eric R. Beckel; Lalgudi V. Natarajan; Vincent P. Tondiglia; Richard L. Sutherland; Timothy J. Bunning; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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 | Electro-optic properties of cholesteric liquid crystals with holographically patterned polymer stabilization were examined. It is hypothesized that increasing the LC domain size in a single dimension, relative to a random 3-D network of LC pockets separated by polymer strands, will allow for enhanced electro-optic properties of the final device. Prior to holographic patterning, polymer stabilization with large elastic memory was generated by way of high irradiation intensities and optimized material ... |
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| Liquid Crystal Bragg Gratings: Dynamic Optical Elements for Spatial Light Modulators (Preprint) |
JAN 2007 |
18 pages |
| Authors:
Richard L. Sutherland; Vincent P. Tondiglia; Lalgudi V. Natarajan; Jeremy M. Wofford; Stephen Siwecki; Gary Cook; Dean R. Evans; Pamela F. Lloyd; Timothy J. Bunning; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SURVIVABILITY AND SENSOR MATERIALS DIV/HARDENED MATERIALS
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| Bragg gratings yield a single diffracted order when irradiated by a coherent beam at the appropriate Bragg angle. In many cases, nearly all of the energy of the incident beam can be coupled to the diffracted beam. Hence these gratings can form many useful optical elements, and this has been realized in 1-D, 2-D, and 3-D photonic crystals. Bragg gratings made with liquid crystals offer the added dimension of dynamic ... |
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| Holographic Polymer Dispersed Liquid Crystal (HPDLC) Transmission Gratings Formed by Visible Light Initiated Thiol-Ene Photopolymerization (Postprint) |
OCT 2006 |
9 pages |
| Authors:
Jeremy M. Wofford; Timothy J. Bunning; Lalgudi V. Natarajan; Vincent P. Tondiglia; Richard L. Sutherland; Stephen A. Siwecki; Pamela F. Lloyd; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| We report on the initial development of a visible initiator for thiol-ene photoplymerization using the 647 nm radiation from a Krypton ion laser. The photoinitiator system consists of the dye oxazine 170 perchlorate and the co-initiator benzoyl peroxide. Electron transfer occurs between the singlet excited state of the oxazine dye and benxoyl peroxide with subsequent decomposition of the peroxide yielding benzoyl oxy radicals capable of free radical initiation. We demonstrate ... |
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| On the Structure of Holographic Polymer Dispersed Polyethylene Glycol (Preprint) |
OCT 2006 |
27 pages |
| Authors:
Timothy J. Bunning; Michael J. Birnkrant; Hillary McWilliams; Christopher Y. Li; Lalgudi V. Natarajan; Vincent P. Tondiglia; Richard L. Sutherland; Pamela F. Lloyd; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
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| Holographic polymerization (H-P) has been used to fabricate polymer dispersed liquid crystals and pattern inert nanoparticles. In this article, one-dimensional grating structures of Norland resin and polyethylene glycol (PEG) was achieved using the H-P technique. Both reflection and transmission grating structures were fabricated. The optical properties of the reflection grating structures (also known as Bragg reflectors (BRs)) are thermosensitive, which can be attributed to the formation and crystallization of PEG ... |
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| On the Structure of Holographic Polymer-Dispersed Polyethylene Glycol (Postprint) |
OCT 2006 |
11 pages |
| Authors:
Michael J. Birnkrant; Hilary K. McWilliams; Christopher Y. Li; Lalgudi V. Natarajan; Vincent P. Toodiglia; Richard L. Sutherland; Pamela F. Lloyd; Timothy J. Bunning; DREXEL UNIV PHILADELPHIA PA
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| Holographic polymerization (H-P) has been used to fabricate polymer-dispersed liquid crystals and pattern inert nanoparticles. In this article, one-dimensional grating structures of Norland resin and polyethylene glycol (PEG) were achieved using the H-P technique. Both reflection and transmission grating structures were fabricated. The optical properties of the reflection grating structures (also known as Bragg reflectors, BRs) are thermosensitive, which is attributed to the formation and crystallization of PEG crystals. The ... |
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