Temperature-Independent Achromatic Liquid-Crystal Grating with Spatially Distributed Twisted-Nematic Orientation

We propose an electrically tunable liquid crystal (LC) grating unit consisting of a conventional homogeneous LC cell and an LC grating with spatially varied twisted-nematic (TN) orientation domains ($-\pi$ to $\pi$). The former cell controls the Stokes parameter $S_{3}$ and the latter functions as a...

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Bibliographic Details
Published inApplied physics express Vol. 5; no. 6; pp. 062501 - 062501-3
Main Authors Honma, Michinori, Nose, Toshiaki
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.06.2012
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Summary:We propose an electrically tunable liquid crystal (LC) grating unit consisting of a conventional homogeneous LC cell and an LC grating with spatially varied twisted-nematic (TN) orientation domains ($-\pi$ to $\pi$). The former cell controls the Stokes parameter $S_{3}$ and the latter functions as a TN-LC grating that is highly sensitive to $S_{3}$. We demonstrate the unique characteristics of the proposed TN-LC grating: it is highly efficient, is almost achromatic, and has minimal temperature-dependent diffraction properties. These properties are a result of the retardation- and wavelength-insensitive polarization rotation nature of general TN-LC cells under Mauguin's condition.
Bibliography:Concept of electrically tunable LC grating unit consisting of homogeneous LC cell and achromatic TN-LC grating whose twist angle varies from $-\pi$ to $\pi$. Polarization microscopy images of (a) $\pm\pi$ and (b) $\pm\pi/2$ twist modes. Period of microrubbing pattern is 80 μm, so $\Lambda=160$ μm in $\pm\pi$ twist mode. (a) Diffraction efficiencies and (b) diffracted beam patterns for different wavelengths, when linearly polarized light is incident on TN-LC grating. Temperature dependence of diffraction efficiency when (a) left-handed and (b) right-handed circularly polarized light is incident on TN-LC grating ($\lambda=633$ nm). Diffraction efficiency as function of controlling voltage applied across homogeneous LC cell (5CB, $d=11.2$ μm), where left-handed circularly polarized light ($\lambda=633$ nm) is incident on cell.
ISSN:1882-0778
1882-0786
DOI:10.1143/APEX.5.062501