Reversible birefringence in microstructures fabricated by two-photon absorption polymerization

This paper reports the fabrication of birefringent microstructures using two-photon absorption polymerization. The birefringence is caused by a light-driven molecular orientation of azoaromatic molecules (Disperse Red 13) upon excitation with an Ar+ laser at 514.5nm. For an azoaromatic dye content of 1% by weight, we obtain a birefringence of 5×10−5. This birefringence can be completely erased by overwriting the test spot with circularly polarized laser light or by heating the sample. Our results open the door to the development of alternative applications in optical data storage, waveguiding, and optical circuitry.