We report a study of diffraction gratings observed in planar cells of nematic mixture (cyanobiphenyl and cyanotriphenyl derivatives, E7) made with different aligning substrates. Under the combined application of very low intensity laser beams (1.8 mW/cm(2)) and low dc voltage (4 V), highly sensitive gratings have been observed in degenerate four-wave-mixing experiments. Beam coupling measurements confirm the photorefractive-like nature of the gratings. Interesting results are obtained using two different liquid crystals, depending on the aligning substrates. The observed behavior suggests the fundamental role of the interfaces in the photoinduced processes.
Surface-induced photorefractive-like effect in pure liquid crystals
PAGLIUSI, Pasquale;CIPPARRONE, Gabriella
2002-01-01
Abstract
We report a study of diffraction gratings observed in planar cells of nematic mixture (cyanobiphenyl and cyanotriphenyl derivatives, E7) made with different aligning substrates. Under the combined application of very low intensity laser beams (1.8 mW/cm(2)) and low dc voltage (4 V), highly sensitive gratings have been observed in degenerate four-wave-mixing experiments. Beam coupling measurements confirm the photorefractive-like nature of the gratings. Interesting results are obtained using two different liquid crystals, depending on the aligning substrates. The observed behavior suggests the fundamental role of the interfaces in the photoinduced processes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.