Fig. 3: Polarising optical microscope (POM) images of the SmC(*) alignment in the VGA-FLC device.

a–f The alignment effects of homeotropic surface-relief gratings on the smectic c-director on a single grating with pitch of 4 µm and peak-to-peak amplitude of 0.3 ± 0.1 µm SU-8 grating, with d = 6.4 ± 0.6 μm, and filled with SCE13-R. a–c Rotations of the gratings between crossed polarisers, showing regions with no gratings showing a schlieren texture, and regions with gratings inducing a preferred c-director orientation. d–f A full wave plate oriented at 45° to crossed polarisers reveals the c-director orientation is perpendicular relative to the grating vector g. This reveals that the smectic layers form an A₂₁ elastic deformation. g–l POM images on cooling VGA-FLC Device¹ (Table 1) at 0.5 °C min⁻¹ into the SmC(*) phase. g T = 59.7 °C (ΔT = 1.1 °C) The dark texture at the SmA to SmC* transition before undulating textures appear, showing good homeotropic alignment. h T = 55.7 °C (ΔT = 5.1 °C) Carpet-like textures arise below the SmA to SmC(*) transition. i T = 55.2 °C (ΔT = 5.6 °C) Carpet textures dissipate behind a dislocation line of layer formation. The number of defects on the grating texture depends on the direction of layer formation flow relative to the grating vector g. j T = 53.7 °C (ΔT = 7.1 °C) Texture free of undulations. k T = 53.7 °C (ΔT = 7.1 °C) Undulations continuously appear and dissipate. l T = 51.2 °C (ΔT = 9.6 °C) The texture on further cooling become optically dark and well aligned, away from the disclinations.