Mid-Infrared Birefringence of Liquid Crystals, Polarimetry, and Intensity Modulator

The Stokes parameters of transmitted light and the birefringence were measured for several liquid crystal mixtures in the mid-infrared spectral range (1900 - 5500 cm-1). A mid-infrared intensity modulator has been fabricated and characterized. Germanium substrates show both sufficient conductivity a...

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Bibliographic Details
Published inThe journal of physical chemistry. B
Main Authors Atorf, Bernhard, Auf der Landwehr, Chris Holm, Rennerich, Roman, Kitzerow, Heinz-Siegfried
Format Journal Article
LanguageEnglish
Published United States 16.01.2019
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Summary:The Stokes parameters of transmitted light and the birefringence were measured for several liquid crystal mixtures in the mid-infrared spectral range (1900 - 5500 cm-1). A mid-infrared intensity modulator has been fabricated and characterized. Germanium substrates show both sufficient conductivity and transparency in the mid-infrared range to serve as transparent electrodes. The modulator makes use of the well-known principle of a twisted nematic cell, which rotates the plane of polarization of a transmitted electromagnetic wave in the field-off state and does not change the state of polarization at sufficiently high voltage. For this application, alignment layers made of poly(vinyl alcohol) and wire grid polarizers on a substrate made of 1,1,2,2-tetrafluorethen (teflon) are used. The modulator shows high contrast ratios.
ISSN:1520-5207