Temperature and polarization dependence of transient gratings in azo-dye-doped liquid crystals

The dynamic behavior of transient gratings (TGs) formed in a planar-aligned azo-dye-doped liquid crystal film is investigated. The temporal profile of the diffraction efficiency of TGs reveals two components corresponding to the fast photoinduced isomerization of azo dye molecules and the slow dye-induced reorientation of liquid crystals. The polarization dependence of diffraction efficiency shows a strong anisotropy of excitation. The temperature dependence of diffraction efficiency and the corresponding relaxation time of decay in the slow component of diffraction reveal a thermal effect on grating formation.