Surface-induced photorefractivity in twistable nematics: toward the all-optical control of gain.
We report the first two-beam coupling investigation of the surface-induced photorefractive effect (SIPRE) in optically twistable nematic liquid crystal cell. The unique space-charge field of SIPRE is exploited to achieve optical tuning of the photorefractive gain. A reconfigurable photoaligning substrate is used to adjust the twist angle, which is proved to be a control parameter for the photorefractive gain. The amplitude of the optical modulation increases gradually with the twist. Its phase shift changes from 0 degrees to 90 degrees with the polarization state of the two interfering beams. These results pave the way to the all-optical control of the photorefractive gain.
Department of Physics, Laboratorio Regionale LICRYL INFM-CNR and CEMIF CAL, Università della Calabria, 87036 Rende, CS, Italy. pagliusi@fis.unical.it
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D008027:Light; D050866:Liquid Crystals / Q000737:chemistry*; D008422:Materials Testing; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation; D013499:Surface Properties