Cooperative interaction in azopolymers upon irradiation

Abstract

We present two optical experiments which permits to evaluate individual and collective behaviours of molecules leading to a well-organized pattern in a randomly activated molecular assembly; in a first experiment a white light and a laser beam are sent together; in a second experiment a low-power coherent beam carrying polarization and wavelength information is used to organize a surface relief grating on a photochromic polymer thin film which is photo-activated by a powerful incoherent beam; we show that collective movements originate at the molecular level.