Photonic crystals for the visible range fabricated by autocloning technique and their application

We fabricate photonic crystals for the visible range by the autocloning technique, in which multilayers are stacked by an appropriate combination of sputter deposition and sputter etching. TiO₂/SiO₂ and Ta₂O₅/SiO₂ are chosen as materials since they are transparent in the range and give a high contrast of refractive indices. The fabrication technique has flexibility regarding materials and size and is very reliable and reproducible even if the pitch is less than 0.2 m. We also study the application of photonic crystals to birefringent elements such as waveplates and polarization selective gratings and experimentally verify that they are useful for optical pick-up systems.