Silicon-Compatible Fabrication of Inverse Woodpile Photonic Crystals with a Complete Band Gap

Three-dimensional (3D) photonic crystals can provide access to very interesting and unique properties for ultimate control and manipulation of photons, not possible otherwise. However, widespread implementation of such photonic crystals remains elusive because the fabrication technology available today has either silicon (Si) incompatibility, poor scalability, a large number of undesired defects, challenging or impossible placement of intentional defects, or has advanced nonstandard process steps available only in a few laboratories. In this work, a new methodology of fabricating 3D photonic crystals free of unintentional defects is developed. This methodology is “truly” Si-compatible and uses techniques available in any standard fabrication facility. A broadband omnidirectional reflector on Si is demonstrated using the same method. Introduction of intentional defect sites for fabrication of 3D waveguides and optical cavities is also discussed.