| The optical properties of nematic liquid crystal E-300 and several polymer-dispersed liquid crystals (PDLC) are studied, both by measurements and theoretical calculations. The calculated light transmission of E-300 cell is in very good agreement with the experimental data. In PDLC's, we observe a delayed component in the switching characteristics. Upon application of square wave electric pulses, the cell response exhibits: (1) rapid increase in transmission with a rise-time of 2–5 ms and (2) relatively slow and complex decay with characteristics. These are significantly different within and outside the applied pulse. The delayed component that provides direct evidence for the reorientation dynamics of nonspherical droplets and/or charges at the liquid crystal-polymer interface in the PDLC cell. At application of sinusoid wave electrical signal, the cell response shows a double frequency sinusoidal wave response. Frequency and field dependent phase shifts are observed. |
