Direct control of disclinations via hybrid planar solitons in nematic liquid crystals

Disclinations are among the most common topological defects in nematic liquid crystals. Their controlled generation is essential for both fundamental studies of defect physics and the development of functional soft-matter systems. However, achieving such control remains challenging. Here, we use laser thermal tweezers in a nematic liquid crystal cell with a free surface to generate a hybrid planar soliton, a structure topologically equivalent to a disclination, as both belong to the same homotopy group, π 1 ( R P 2 ). This soliton acts as a template for guiding the formation of disclinations with prescribed geometries and positions. To the best of our knowledge, this represents the first practical implementation of soliton–disclination conversion for direct and predictable defect control. These results elucidate the topological connection between planar solitons and disclinations and provide a foundation for precise topological patterning in liquid crystal systems.