Generation of the Planar Solitons Using Thermal Trapping of a Disclination in Nematic Liquid Crystals and Their Applications

Abstract The mesophase properties of nematic liquid crystals render them ideal for controlling and studying topological defects. The planar soliton, a π‐wall in the form of a string with a constant thickness shown in a nematic, is a topological defect lacking singularity. Herein, a thermal laser tweezer is introduced to trap the disclination at the isotropic–nematic interface induced by the thermal effect and to move the trapped disclination under the low anchoring condition, which enables to generate solitons as if they were drawn and to control them actively. The soliton, which is created or annihilated in accordance with topological charge conservation, exhibits cosmic string intercommutation. Thus, the dynamics of cosmic strings can be implemented by using solitons in a nematic. To demonstrate potential applications of the solitons, microsized cargo delivery and polarization diffraction gratings are presented, which could be used in lab‐on‐a‐chip and implemented in various photonic applications, respectively, and prove the applicability of a topological defect through complete control.