Electrically controlled surface diffraction gratings in nematic liquid crystals.
Photorefractive diffraction gratings were studied in cells of homeotropically aligned pentyl-cyanobiphenyl liquid crystal. These holographic gratings were induced by the simultaneous and nonsimultaneous application of dc and coherent optical electric fields. The observed behavior was consistent with a predominantly surface-mediated photorefractive effect. Beam coupling was observed in all cases and led to a model involving screened and unscreened interfacial trapped charges driving a modulation of the easy axis. Holographic gratings could be switched on and off by the application of a small voltage.
Zhang
J
J
Ostroverkhov
V
V
Singer
K D
KD
Reshetnyak
V
V
Reznikov
Y
Y