Total-Reflection Switch Using High-Tilt-Angle Cholesteric-Smectic C* Phase Transition Ferroelectric Liquid Crystal

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Abstract
A total internal reflection (TIR) microoptic switch using high-tilt-angle materials showing cholesteric-smectic C* phase transition for multimode fiber is described. The device shows excellent temperature-independent electrooptic characteristics and exploits the maximum contribution of ferroelectric liquid crystal (FLC) birefringence. The switch shows asymmetric response and unusual nonlinear behaviour, which is analysed by polarisation reversal current. The nonlinear response is due to the polar surface interaction which behaves as if it were positively charged and has been analysed by the transmission characteristics and by current analysis on applying square and triangular waves of various frequencies. The switch has a switching response of ∼20 ms limited due to monostable surface conditions, and shows a beam attenuation of ∼5×107 in the off state.