Figure 4. Thermally and electrically assisted topological reconfiguration at fixed pitch.

Demonstration of topological transformations under the application of thermal (left part) and electrical (right part) fields for cholesteric droplets with perpendicular surface anchoring and pitch p=55 μm. All pictures correspond to XPOL imaging. Thermal case (see symbol ‘T'): droplet diameter d=85 μm, N=3.1. For each cycle, the liquid crystal is heated above the nematic–isotropic transition temperature and then cool down at room temperature, three distinct states are shown in a–c. Electrical case (see symbol ‘E'): droplet diameter d=67 μm, N=2.4. For each cycle, a 10-V_rms voltage at 2-kHz frequency is applied on the ≈250-μm-thick film in which the droplet is immersed, three distinct states are shown in d–f. Scale bars, 25 μm.