Fast Integrated Electro-Optical Switch and Beam Deflector Based on Nematic Liquid Crystal Waveguides

In this paper, the design, the realization, and the experimental characterization of an integrated electro-optical switch and a beam deflector, both based on planar nematic liquid crystal (NLC) waveguides, are reported. In order to test such devices, a particular waveguide structure consisting of a three-stage device, having a thin nematic LC film as the middle stage and two glass waveguides as the other stages, has been designed and realized. The electro-optical behavior and the response time have been studied for different configurations for both TE and TM polarized light. By a proper choice of the material parameters and because of the presence of an additional constant bias voltage, we got response time in the microsecond range. The experimental results obtained are very promising in the frame of integrated electro-optical devices, even if the effect underlying the results is not yet understood and probably needs some deeper research into liquid crystal physics and surface interactions.

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