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Proceedings Paper

Holographic studies on block copolymers
Author(s): Michael Haeckel; Lothar Kador; Carsten Frenz; Hans-Werner Schmidt
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Paper Abstract

The optically induced birefringence in different azobenzene and mesogen containing block copolymers has been studied with holographic methods as well as with measurements between crossed polarizers. The influence of various parameters for possible applications as holographic data storage materials was investigated. In the block copolymers, the functionalized blocks are confined in a matrix of polystyrene. This has the advantage that no surface relief gratings appear when the chromophores are reoriented. Also liquid-crystalline stabilization due to cooperative reorientation occurs inside the functionalized blocks. These short-distance interactions in the blocks give rise to long-term stability of the inscribed gratings. So far injection-molded blends with azobenzene containing block copolymers were capable to store up to 200 holograms on one spot. On such a sample we could also demonstrate a fundamental physical effect which generally plays a role for light diffraction on thick gratings. According to the Kramers-Kronig relations, an attenuation of light is always coupled with a phase shift. In the case of a thick holographic grating, the intensity of the transmitted wave (of diffraction order zero) is a function of the angle of incidence, because part the light is diffracted into the first order when the Bragg condition is fulfilled. We measured the phase shift of the transmitted wave as function of the Bragg mismatch angle and found good agreement with analytical calculations.

Paper Details

Date Published: 26 October 2004
PDF: 10 pages
Proc. SPIE 5521, Organic Holographic Materials and Applications II, (26 October 2004); doi: 10.1117/12.563819
Show Author Affiliations
Michael Haeckel, Univ. Bayreuth (Germany)
Lothar Kador, Univ. Bayreuth (Germany)
Carsten Frenz, Univ. Bayreuth (Germany)
Hans-Werner Schmidt, Univ. Bayreuth (Germany)


Published in SPIE Proceedings Vol. 5521:
Organic Holographic Materials and Applications II
Klaus Meerholz, Editor(s)

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