Shaping and positioning of topological defects in nematic liquid crystal cells equipped with patterned electrodes

Jieh-Wen Tsung*, Bo Yao Chen, Ya Zi Wang

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations


Generation of topological defect that has a particular type (topological charge) and specific shape (radial, spiral, or circular) on a designed position is a crucial step in producing q plates and defect-mediated self-assembled micro structures. Shaping and positioning of topological defects can be achieved by applying delicately designed electric field on nematic liquid crystal (NLC). The guidelines for the electrode design are provided in this paper. The following are the three frequently asked questions: 1) What kinds of defects can exist in NLC? Points, lines, or walls? 2) How to generate a defect with a particular topological charge by setting proper boundary condition? 3) How to control the orientation of liquid crystal to have a defect with desired vorticity? The three questions can be answered by the three theories in physics: 1) Symmetry breaking in ordered material, 2) Euler characteristic and vectors in closed confinement, and 3) Minimization of free energy of NLC in electric field. Topological defects in spherical and toroidal confinements were generated in NLC cell and examined under polarized microscope. Radial and circular hedgehog defects were successfully created by fishbone- and coil-shaped patterned electrodes, respectively. By applying the three physical theories in NLC cell design, topological defects were successfully arranged in square and hexagonal arrays. They are large, stable, and re-configurable, and the applications in optics are demonstrated.

Original languageEnglish
Title of host publicationEmerging Liquid Crystal Technologies XV
EditorsLiang-Chy Chien, Dirk J. Broer, Igor Musevic
Number of pages14
ISBN (Electronic)9781510633698
StatePublished - 25 Feb 2020
EventEmerging Liquid Crystal Technologies XV 2020 - San Francisco, United States
Duration: 3 Feb 20205 Feb 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceEmerging Liquid Crystal Technologies XV 2020
Country/TerritoryUnited States
CitySan Francisco


  • Nematic liquid crystal
  • Patterned electrode
  • Topological defect


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