Pattern forming instability induced by light in pure and dye-doped   nematic liquid crystals
  We study theoretically the instabilities induced by a linearly polarized ordinary light wave incident at a small oblique angle on a thin layer of homeotropically oriented nematic liquid crystal with special emphasis on the dye-doped case. The spatially periodic Hopf bifurcation that occurs as the secondary instability after the stationary Freedericksz transition is analyzed. 
D.O. Krimer, G. Demeter, and L. Kramer