Development of fiber optic liquid crystal sensor for pressuremeasurement

摘要

The paper presents a further development of a novel fiber opticlow and high hydrostatic pressure sensing technique utilizing newclasses of chiral nematic liquid crystals with a significantly reducedthermal sensitivity. The low-pressure sensor (up to 1 MPa) is based onpolarization effects caused by strong rotatory power of chiral nematicsand pressure-induced deformations of a twisted nematic cell. Thehigh-pressure sensor (up to 60 MPa) is based on intensity phenomenaoccurring in novel classes of chiral nematics with induced smecticA_d phase. The latest results indicate that our method ofhydrostatic pressure measurement offers high response to pressure withreduced temperature sensitivity and, depending on the employedconfiguration and on the liquid crystalline sensing head, can be pre-setfor a required range of pressure