Phase transitions and switching behaviour in thin (1.5 - 4 ?m) planar cells of a ferroelectric liquid crystal (FLC) mixture are studied by optical second harmonic generation (SHG). A pronounced anisotropy of the SHG response shows a high ordering degree of the FLC molecules in the cells. We studied the electric field-induced switching of the FLC cells and their temperature dependence by means of SHG. This shows the existence of a 10-20 nm thick frozen sub-surface layer of FLC molecules,which cannot be switched by an electric field well above the bulk saturating field and at significantly high temperatures.
Second harmonic generation studies of phase transitions in ferroelectric liquid crystals
Soria;
2002
Abstract
Phase transitions and switching behaviour in thin (1.5 - 4 ?m) planar cells of a ferroelectric liquid crystal (FLC) mixture are studied by optical second harmonic generation (SHG). A pronounced anisotropy of the SHG response shows a high ordering degree of the FLC molecules in the cells. We studied the electric field-induced switching of the FLC cells and their temperature dependence by means of SHG. This shows the existence of a 10-20 nm thick frozen sub-surface layer of FLC molecules,which cannot be switched by an electric field well above the bulk saturating field and at significantly high temperatures.File in questo prodotto:
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