All-optical reversible actuation of photochromic-polymer microsystems

Optomechanical actuation of polymer films doped with spiropyran photochromic molecules is demonstrated by the reversible bending of the films upon laser irradiation (see Figure). The photoactuators are fully wavelength controllable and capable of operating reversibly in a few seconds. The reversible macroscopic mechanical effect is found to be associated with the interactions between different stereoisomers and formation of merocyanine aggregates.