Holographic chiral structure on the basis of Weigert's effect.

A simple analysis of the possibility of creating a holographic chiral structure on the basis of Weigert's effect with help of the Jones vector-matrix method was done, to my knowledge, for the first time. A corresponding experiment was also conducted. The results of the investigation show that the diffractive optical element obtained behaves similarly to liquid crystals or sculptured thin films with chiral structures.

One more possible mechanism of Weigert's effect in azo-dye-colored materials.

One of the purposes of investigating the mechanisms of Weigert's effect in azo-dye-colored materials is the search for ways to improve their corresponding characteristics. So far the suggested mechanisms based on the isomerization process of the molecules of the dyes do not account for some facts that take place in this case. I present some results of the investigation of Weigert's effect in azo-dye-colored materials and propose a possible new mechanism.

Trans-cis isomerization and the blue phases.

A new class of photoactive chiral liquid crystals based on a photoactive nematic host material and a photoinactive chiral dopant was utilized to investigate the behavior of the blues phases when trans-cis isomerization is induced. While the general behavior follows what has been observed in the cholesteric phase, the sensitivity of the blue phases to external parameters causes different behavior when these systems are exposed to UV radiation. The results for four different mixtures are reported and include (1) modulation of the blue phase selective reflection wavelength with low levels of UV and visible light, (2) conversion of one blue phase to another upon exposure to UV light, and (3) induction of blue phases due to UV irradiation when no blue phases are stable beforehand.