GRATING COUPLED LIQUID-CRYSTAL WAVE-GUIDES USING NEMATICS AND SMECTICS

The optical properties of grating coupled waveguides are theoretically modeled and practically demonstrated using nematic and smectic liquid crystals as thin (0.7 mum) waveguide layers. Voltage induced reorient ation of the liquid crystal is shown to lead to large changes in refle ctivity and transmissivity when the angle of incidence initially corre sponds to a guided mode resonance. Time resolved measurements using th ese thin cells show that the switching time for the nematic phase can be faster than the smectic phase.