Study On The Modulation Of Nematicons And Topological Disclination Behaviors In Nematic Liquid Crystals

Spatial optical solitons are beams that can achieve non-diffraction propagation in nonlinear media.When a light is incident into a nonlinear medium,the nonlinear refractive index modulation produced by the medium will balance the diffraction effect of the beam.The beam can then form spatial optical solitons.Spatial optical solitons have been a popular topic of research in nonlinear optics,and it has very important applications in research fields such as all-optical communication,optical logic,and optical computing.The nematic liquid crystal is an excellent nonlocal nonlinear medium for the study of spatial optical solitons.However,achieving a very large angular deflection of spatial optical solitons in nematic liquid crystals has been one of the main issues hindering the application of spatial optical solitons.Methods for the deflection of nematicon and nematicon pairs by doping dielectric particals and customizing electrodes are presented in this paper and a completely new concept is proposed:large-angle deflection of spatial optical solitons is achieved by utilizing randomly formed topological soliton defects in nematic liquid crystals.The strong interaction between spatial optical solitons and topological soliton defects in nematic liquid crystals has attracted us to investigate the topological soliton defects in detail.We have realized the fabrication of arbitrarily shaped disclination using the digital micro-mirror device-based microlithography system.In addition to the disclination structure,non-singular wall structure and no-disclination structure can be generated in nematic liquid crystal,where the non-singular wall structure produces a perpendicular liquid crystal molecule directional vector distribution inside the substrate to avoid topological discontinuity,and the no-disclination structure avoids the formation of disclination by introducing chiral distortion inside the liquid crystal and forms a special structural color.Finally,we developed liquid crystal devices with a unique mechanical response based on the self-assembly behavior of disclination structures under stress,which manipulates the long-distance transport and rotation of micron-sized silica particles by designing complex patterns of disclination paths.These applications further broaden the field of application in nematic phase liquid crystals,making nematic defect lines an ideal platform for studying the manipulation of micro-and nanoparticles.