Optically induced extraordinarily large negative orientationalnonlinearity in dye-doped liquid crystal

Laser induced large negative reorientational nonlinearities are observed in dye-doped liquid crystal. The effect is attributed to intermolecular torque exerted by the photoexcited dye molecules, which causes the liquid crystal axis to realign in a direction orthogonal to the optical electric field. Optical nonlinearity as large as 10^-2 cm²/W in a 37-μm-thick sample has been observed. In some highly absorptive dyed liquid crystal, the orientational effect can be much larger than the thermal effect