High-speed sensor head with wide frequency range using deformed helix ferroelectric liquid crystal

Abstract

In this paper we propose a new approach to fiber-optic sensor head based on voltage-controlled ferroelectric liquid crystals (FLC). Using nano-grid electrodes, nanometer-scale photo-alignment layers and deformed helix ferroelectric liquid crystals with a sub-wavelength helix pitch of 150 nm, we have realized a fully integrated polarization-based photonic transducer which exhibits fast response to an applied voltage/electric field, excellent linearity and allows multiplexing using standard, low cost telecom optical fibers. In addition, the electro-optical behavior of deformed helix ferroelectric (DHF) liquid crystal in reflective mode is described and tested. The electrically controlled reflectance has been measured at sub-kilohertz driving voltage frequency for different polarizations of the incident light and compared quite successfully with the simulation results.