Electrically switchable reflection holograms formed using two-photon photopolymerization
Autor: | S. M. Kirkpatrick, Vincent P. Tondiglia, D.W. Tomlin, Timothy J. Bunning, L. V. Natarajan, D.J. Pikas |
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Rok vydání: | 2002 |
Předmět: | |
Zdroj: | Applied Physics A: Materials Science & Processing. 74:767-772 |
ISSN: | 1432-0630 0947-8396 |
Popis: | Two-photon holographic photopolymerization was used to form switchable Bragg gratings composed of layers of phase-separated liquid-crystal (LC) domains interspersed with cured, crosslinked polymer. These holographic polymer-dispersed liquid crystals form a periodic structure which diffracts red light due to nanostructured planes ∼250 nm in spacing. These structures were formed by interfering two 90-fs pulses coherently upon a reactive syrup consisting of acrylate monomer, liquid crystal, and a two-photon dye. The large two-photon cross-section allows excitation of the two-photon dye that results in electron transfer between this dye and the monomer. Diffraction efficiencies of approximately 10% were obtained, which can be modulated using an electric field applied across the film. Switching speeds below 1 ms were observed due in part to the small size of the LC domains. |
Databáze: | OpenAIRE |
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