In recent years there has been much interest in the physics and possible technological applications of liquid crystal-based tuneable Bragg gratings. Such optical devices can be realised using special composite materials based on a sequence of polymeric sheets alternated by layers containing only liquid crystal, sometimes known as Policryps and Poliphem. Recent experiments have clearly demonstrated a peculiar dependence of relaxation times on actual external field applied (both amplitude and duration) after switching off the operating voltage. We propose a theoretical model of director reorientation in such composites, in which both bulk behaviour in the LC stripes and interfacial polymer-LC interaction is taken into account. Within this model we explain the dynamical behaviour of holographic gratings characterized by a nematic film-polymer slice sequence structure, as well as other polymer-LC phase separated composites.

Modelling the dynamical behaviour of holographic gratings with nematic film-polymer slice sequence structure / Shelestiuk, S. M.; Reshetnyak, V. Y.; Abbate, G.; Marino, A.; Vita, Francesco. - In: MOLECULAR CRYSTALS AND LIQUID CRYSTALS. - ISSN 1542-1406. - STAMPA. - 508:1(2009), pp. 14-23. [10.1080/15421400903057975]

Modelling the dynamical behaviour of holographic gratings with nematic film-polymer slice sequence structure

VITA, Francesco
2009-01-01

Abstract

In recent years there has been much interest in the physics and possible technological applications of liquid crystal-based tuneable Bragg gratings. Such optical devices can be realised using special composite materials based on a sequence of polymeric sheets alternated by layers containing only liquid crystal, sometimes known as Policryps and Poliphem. Recent experiments have clearly demonstrated a peculiar dependence of relaxation times on actual external field applied (both amplitude and duration) after switching off the operating voltage. We propose a theoretical model of director reorientation in such composites, in which both bulk behaviour in the LC stripes and interfacial polymer-LC interaction is taken into account. Within this model we explain the dynamical behaviour of holographic gratings characterized by a nematic film-polymer slice sequence structure, as well as other polymer-LC phase separated composites.
2009
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11566/228985
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