Fabrication and Characterization of Photonic Crystals by Two-Photon Polymerization Using a Femtosecond Laser

Two-photon polymerization is a powerful technique in fabricating three dimensional sub-diffraction-limited structures. Recently, new sol-gel material, SZ2080, was introduced into two-photon polymerization and was proved to be better than the conventional materials for its negligible shrinkage. In this paper, two-photon polymerization was applied to generate woodpile structures, one kind of photonic crystal, using SZ2080. First, the relationship between scanning speed, laser power and resolution was determined through fabricating free-hanging lines. Based on this relationship, woodpile structures with different period distances were fabricated with high uniformity as shown by SEM images. Then optical properties of woodpile structures were investigated using Fourier Transform Infrared Spectroscopy (FTIR) and a quantitative relationship between band gap and period distance was established.