Light propagation through photoinduced chiral structures in azobenzene-containing polymers

Abstract

We investigate light propagation through azobenzene-containing polymers with photoinduced chiral structures. The structures have large pitch but the Mauguin condition is not fulfilled. The eigenmodes are shown to be elliptical and their ellipticity is determined by the ellipticity e0 of the exciting light. In amorphous azopolymers, light induces a macroscopic chiral structure comprising the whole illuminated region. The pitch depends on the value of e0: no chirality is induced if e0 = 1 (circular polarization). In liquid-crystalline azopolymers circularly polarized light induces the formation of many microscopic spirals, which makes the material equivalent to the classical optically active media.