Dynamics of photoalignment in azo-dye-doped liquid crystals

A transmitted light without analyzer was led into the pump-probe twist nematic experiment in azo-dye-doped liquid crystals to observe the light scattering from the dye-adsorbed surface during photoalignment. The morphology of the dye-absorbed surface monitored by this transmitted light is correlated with the formation of the ripple structure, which is reflected by the anchoring of the dye-adsorbed layer, which is, in turn, revealed by measuring the surface director reorientation angle throughout the process. As the regular ripple structure is gradually formed, the Rayleigh scattering is transferred to the Mie scattering since the scale of the ripple structure is at the wavelength.