Perdeuterated liquid crystals for near infrared applications

• Properties of highly isotopically pure liquid crystalline material are compared with non-deuterated analogue.
• Mueller matrix approach applied to liquid crystal cell.
• Decoupled individual polarization properties of deuterated and non-deuteriated LCs using Polar decomposition method.
• Evaluation of modulation properties of deuteriated liquid crystal in near infrared.

For majority of Liquid Crystalline compounds the absorption occurs at two spectral regions: ultraviolet UV (due to electronic excitations) and infrared IR (caused by molecular vibrations). Both cause the absorption which deteriorates electro-optical modulation abilities of LC. In the MWIR and LWIR regions, there are many fundamental molecular vibration bands. The most intense are the ones with high anharmonicity, which in the case of LCs corresponds to the CH bonds, especially present in the aliphatic chains. In the NIR region, overtone molecular vibration bands derived from IR region begin to appear. In the case of CH bond system, the first overtones are present at 1.6–1.7 μm. To reduce NIR absorptions, perdeuterated Liquid crystal has been proposed. In this paper, we report the physical and optical properties of liquid crystals based on polarimetry measurements method. We also provide a polar decomposition of experimentally measured Mueller matrix in order to determine polarization properties of the device such as depolarization and diattenuation which cannot be obtained from absorption spectra.

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