Optimizing the nematic liquid crystal relaxation speed by magnetic field

Nematic liquid crystalline materials have been widely used in electro-optical control of visible light. However, when IR light is considered, the thickness of the liquid crystal layer must be increased which causes the relaxation time of the material to be slower than required for many applications. In this paper we use a magnetic field to increase the speed of thick nematic devices. We show that above a particular magnetic field strength, thicker cells relax more quickly than thinner ones. Also, we find that there exists an optimal voltage range for devices of a particular thickness and with a particular applied magnetic field. Devices that allow a half-wave modulation of 1.55 mum light in less than 5 ms are shown to be possible with the use of a 2 T magnetic field. (C) 2004 American Institute of Physics.