Reznikov Y, Ostroverkhova O, Singer KD, Kim JH, Kumar S, Lavrentovich O, Wang B, West JL
Institute of Physics of National Academy of Science, Prospect Nauki 46, Kyiv 252022, Ukraine.
Phys Rev Lett. 2000 Feb 28;84(9):1930-3. doi: 10.1103/PhysRevLett.84.1930.
We observed light-induced alignment of the nematic liquid crystal, 4, 4(')-n-pentylcyanobiphenyl (5CB), on a fused quartz. Irradiation of the adsorbed layer with polarized ultraviolet light produced homogeneous alignment in a 5CB-filled liquid crystal cell with the easy orientation axis perpendicular to the polarization direction. The measured anchoring energy increases with illumination up to 10(-4) erg/cm (2). Phase retardation and pretilt measurements confirmed near homogeneous alignment of the LC in a cell, while the polarization dependence of second harmonic generation suggested a near normal alignment of the adsorbed layer. We believe that light-induced rearrangement or phototransformation of the adsorbed layer causes the observed phenomenon.
