Localized room temperature photo-induced poling of azo-dye-doped polymer films for second-order nonlinear optical phenomena

A novel method for preparing, at room temperature, films of azo-dye-doped polymers with polar order for second-order nonlinear optical applications is demonstrated. The films based on Disperse Red 1 and PMMA have been poled at room temperature by simultaneously applying a DC electric field and irradiating the sample with light from an argon-ion laser. The polar order induced by poling may be destroyed using the irradiation alone. The ability to induce polar order in specific regions and to form patterns of such poled regions using either of these techniques is demonstrated. The mechanisms behind these processes, which involve a trans-cis-trans-isomerization cycle of the dye molecules, are discussed.