Three-dimensional photonic crystals based on double-angled etching and wafer-fusion techniques

We propose a method for the realization of three-dimensional photonic crystals by combining a wafer-fusion technique with a two-stage angled etching process. Etching at an angle of 45° to the substrate creates woodpile (or stacked striped) structures, and artificial defects and light emitters can then be introduced by the wafer-fusion technique, thereby considerably reducing the number of processes required. Here, we determine the required thickness of the photonic crystals by calculating the transmission properties and quality factors of point-defect cavities. Furthermore, we demonstrate the feasibility of angled etching using an inductively coupled plasma-etching system at cryogenic temperatures.