Investigation of the transient symmetric H state in a pi cell

Abstract

The so-called symmetric H (H-s) state has been reported to have submillisecond response times, which results from the symmetric profile of the liquid crystal director; however, no direct evidence has been obtained to show the profile symmetry. The difficulty in proving this symmetric structure by direct observation results from the short lifetime of H-s state (typically around a few tens of milliseconds). In the work reported here, the authors utilize a burst driving method along with stroboscopic illumination from blue and red light emitting diodes to capture conoscopic images for the H-s director profile; these showed good agreement with their modeling. (c) 2007 American Institute of Physics.