Photoinduced superstructural chirality in photochromic polymer: A viable route to light polarization control

Experimental evidence of the supramolecular chiral structures induced in an absorbing medium, namely a non-chiral azo copolymer, by means of the irradiation with circularly polarized light is presented . The polymeric film undergoes a light-induced inhomogeneous modification of its supramolecular organization, both in the transverse and longitudinal directions. The new structure shows optical activity and influences the propagating light beam, determining a polarization conversion from circular toward linear. The optical activity sign can be controlled by the handedness of the inducing circularly polarized light. The observed supramolecular chiral structures, of both circular and spiral shape, exhibit long time stability and complete reconfigurability, paving a new route to light-by-light polarization control and show the interesting possibility to manipulate the light polarization.