Polarisation sensitive optical phase conjugation in novel polymer films

Abstract

The observation of polarisation sensitive optical phase conjugation through degenerate four-wave mixing in polymer films containing azo-based dyes is reported. Two material systems are compared, one in which the chromophores are distributed randomly in a glassy matrix, and a second system in which the chromophores are chemically attached to the polymer molecules. The latter material exhibits a significantly enhanced polarization sensitive phase conjugate signal over the simple mixture. In contrast, degenerate four-wave mixing experiments involving beams with parallel polarisations show similar levels of the phase conjugate signal with these two material systems. The former improvement is attributed to the inhibition of rotation and large scale diffusion of the chromophoric units through the inherent chemical connectivity of the polymer system which also acts to inhibit permanent bleaching. These results highlight the subtle but central role of the polymer matrix in this class of materials.