N-Phenylated aromatic polyurea: a new non-linear optical material exhibiting large second harmonic generation and u.v. transparency

Abstract We report for the first time a non-linear optical polymer exhibiting optical transparency down to 307 nm. From the Maker fringe measurements, the non-linear optical d 33 coefficient of poled aromatic polyurea films was found to be 14 times that of potassium dihydrogen phosphate (KDP) at 1.064 μm fundamental radiation. Aromatic polyurea forms flexible, colourless and transparent films and thermogravimetric analysis showed high thermal stability. The non-linear efficiency and optical transparency make aromatic polyurea a potentially useful material for non-linear optics.