Fabrication of Three‐Dimensional Micro Photonic Crystals of Resin‐Incorporating TiO 2 Particles and their Terahertz Wave Properties

Three‐dimensional (3D) photonic crystals with a diamond structure made from 40 vol% TiO 2 –acrylate dielectric composites were formed by means of a CAD/CAM micro‐stereolithography system. The lattice constant of the diamond unit cell was 500 μm and the forming accuracy was 10 μm. The photonic band gap in the Γ–X 〈100〉 direction measured by terahertz‐time‐domain spectroscopy appeared at 280–360 GHz, which agreed fairly well with the band gap calculated by the plane wave expansion method.