Fig. 4. POM images and schematic illustration of the switching mechanism between modes of the USH-CLC SW, (a) FC textures (scattering state) observed under an AC field of 40 V at 20 Hz, (b) dynamic FC textures (scattering state) after the field is switched off, (c) VA textures (transparent state) under an AC field of 60 V at 1 kHz, and (d) VA textures with small domains (transparent state) after the field is removed. POM observations were performed using crossed polarizers, where P and A indicate the transmission axes of the polarizer and analyzer, respectively. The cones drawn in (d) are to illustrate that the nano helices axis may precess around the normal to the substrates, but on average, the optic axis is along the normal.