Extended Data Fig. 1: Hexagonal colloidal platelet with azobenzene monolayers dispersed in a nematic LC.

a, Three-photon excitation fluorescence microscopy images of a platelet in an LC cell, obtained at the cross-sectional plane (x–z plane) passing through the middle of the platelet, and at the vertical plane (x–y plane) that is orthogonal to the plane of the cell and the large-area faces of the platelet. Both planes pass through the centre of mass of the particle. b, Scanning electron microscopy image of an individual platelet placed on a substrate. c, Schematic of a platelet suspended in a nematic LC. Green rods indicate the director field n(r); red rods indicate the orientation of the azobenzene molecules on the surface of the platelet; the black semi-sphere on one of the vertices of the hexagon represents the surface point defects called ‘boojums’. The optical torque that rotates the platelet away from its equilibrium state is balanced by the counteracting elastic torque caused by director twisting, as shown by the blue and red curved arrows.