Fig. 1: Electrically-tunable disclination line.

Left: Schematic of the fabrication procedure showing a cross-section of the LC device. Blue rods show the orientation of liquid crystal molecules, red circles indicate the defect position and red ribbons represent polymer network. a Initially the device is driven into the bend state (V-state) by applying a voltage above V_c, before 2PP-DLW is used to create a polymer wall stabilised in the V-state. b The applied voltage is removed and the device relaxes to the splay state (H-state). A defect forms next to the V-state wall, separating the topologically discontinuous states. 2PP-DLW is then used to fabricate a polymer-stabilised H-state wall 100 µm from the first wall. c The final configuration of the device, with two parallel polymer-stabilised walls, in the topologically discontinuous H and V states, respectively, separated by a gap of 100 µm. Right: Polarising optical microscopy (POM) images and director profiles showing the dynamics of the tunable disclination line under an applied voltage. Red arrows highlight the position of the defect line in each POM image. d With no voltage applied, the bulk of the device is in the H-state and the defect is adjacent to the V-state wall. e–g A voltage above V_c is applied to the device and the defect begins to move across the channel until it meets the H-state wall. h–j Removing the voltage causes the V-state to relax into a 180° twisted state (T-state), and the defect moves back across the channel. The H-state grows and moves across the channel with the disclination line at the frontier of the growing domain, until it is impeded by the polymer-stabilised V-state wall.