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Observation of symmetry breaking in photoalignment-induced periodic 3D LC structures
Ist Teil von
Journal of molecular liquids, 2020-05, Vol.306, p.112864, Article 112864
Ort / Verlag
Elsevier B.V
Erscheinungsjahr
2020
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
We report on the optical analysis of 3D periodic LC nematic structures, using crossed-polarizer transmission microscopy with oblique illumination. The structure is developed in a cell with orthogonally arranged top and bottom photoaligned periodic micro-patterns. We demonstrate experimentally that two unit cell director configurations can be formed in the device. The size of the unit cell is two times larger than the period of the micropattern because symmetry breaking allows avoiding disclinations lines in the bulk of the liquid crystal. As a result, each unit cell can be located in four equivalent positions. Q-tensor finite element simulations show that the two unit cells have different elastic energy. Oblique illumination transmission experiments are in good agreement with numerical simulations. The observed structures are interesting for optical manipulation purposes, liquid crystal based lasing, geometric phase implementation and many other photonics applications.
•periodic photo-alignment is a novel method for generating 3D soft structures.•all-optical methods are used to realize and analyze the geometry of 3D structures.•finite element simulation helped to validate the unit cell director configuration.•symmetry breaking in the structure exhibits two states with the opposite chirality.•possible applications of the structures: smart windows, holography, LC lasing media.