Microscopic-characterization of photo-induced birefringence of azo-polymer thin film by focused surface plasmon

Abstract

In this paper, we develop a technique to quantitatively evaluate the orientational dependence of local anisotropic properties (of azo-polymers fabricated in the form of thin films ∼ 100 nm) by means of focused surface plasmon. The magnitude of photo-induced birefringence and orientation of fast axis at microscopic sites in thin films are extracted by the developed method on evaluating the propagation constants of surface plasmon obtained from the elliptical absorption pattern in the reflected spatial frequency distribution. Low birefringence (∼0.01) has been successfully measured with ultra-low probe volume.