Reversible Photoinduced Chiral Structure in Amorphous Polymer for Light Polarization Control

Photoinduced supramolecular chiral structures in amorphous and nonchiral azo copolymer are demonstrated using circularly polarized light. The polymeric film undergoes a light-guided inhomogeneous supramolecular modification, both in the transverse and longitudinal directions. The photoinduced structure strongly affects the polarization state of the light propagating in it. Conversion from circular toward linear polarization occurs, and optical activity of the material arises. The direction of the optical rotation (clockwise or anticlockwise) can be controlled by means of the handedness of the inducing CPL. The resulting chiral structures, circular and spiral, exhibits interesting possibility to manipulate the light polarization, showing long-time stability and full reconfigurability.