Photonic crystal structures with submicrometer spatial resolution achieved by high power femtosecond laser-induced photopolymerization

We demonstrate in this paper a fabrication of three-dimensional microstructures using photopolymerization of resin by two-photon absorption. When a tightly focused laser beam was scanned in a light-curling liquid, solidified rods were formed following the trace of the scanning. If the solidification was arranged to occur along the frame of a microstructure, a designed spatial pattern would be transformed into material object. Due to a quadratic dependence of photopolymerization rate on the laser pulse energy, the size of solidified voxels was controlled down to submicrometer order. Infrared transmission measurement exhibited pronounced band gap effects from thus-fabricated photonic crystal structures.