SATHAYE Kedar¹, DUPONT Laurent¹, DE BOUGRENET DE LA TOCNAYE Jean-Louis¹

Article de revue avec comité de lecture

Optical engineering, mars 2012, vol. 51, n° 3, pp. 034001-1-034001-7

2012

In optical telecommunication the need for switchable reflecting devices has often been expressed for wavelength routing or optical monitoring.1 The conventional method to realize these filters is to design a Bragg filter. However, these structures are obtained with very expensive technologies, as they are produced on substrates or photo-written in optical fibers. In this article, we test the cholesteric liquid crystal (CLC), which is a self-organized material owning the optical properties structurally well suited to reach these technical objectives: The CLC has almost the same properties as nematic except for a helical structure of the director. The helical axis is perpendicular to the director and this helix is characterized by the pitch. This periodic structure exhibits a periodical birefringence modulation that causes selective reflections of a circularly polarized light. The dielectric tensor is also undergoing a precession along the helical axis. Due to this structure, these liquid crystals have unique and very attractive optical properties

1 : OPT - Dépt. Optique (Institut Mines-Télécom-Télécom Bretagne-UEB)

Liquid crystal device, Cholesteric, Filters

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