Fabrication of three-dimensional photonic crystals with multilayer photolithography

We have developed a new approach for the fabrication of three-dimensional (3D) photonic crystals based on multilayer 3D photolithography. This method, which uses commercially available photoresist, allows batch fabrication of 3D photonic crystals (PhCs), possesses the flexibility to create a variety of different lattice arrangements, and provides the freedom for arbitrary defect introduction. We describe in this paper how planar lithography is modified to achieve 3D confined exposure and multiple resist application. We demonstrated the fabrication of multilayer "woodpile" structures with and without engineered defects. We further infiltrated the resist template using a higher-index material and obtained the inverse 3D PhC structure.