One-dimensional photonic crystal cavities in single-crystal diamond

The realization of efficient optical interfaces for nitrogen vacancy centers in diamond is an important problem in quantum science with potential applications in quantum communications and quantum information processing. We describe and demonstrate two techniques for fabricating one-dimensional photonic crystal cavities in single-crystal diamond, using (1) a combination of reactive ion etching and focused ion beam milling and (2) transferred silicon hard mask lithography with reactive ion etching. We use two kinds of one-dimensional photonic crystal cavity designs and discuss their optical performances. We find that transferred silicon mask lithography results in better optical properties than focused ion beam patterning techniques. The silicon masks also exhibit high oxygen plasma etching selectivity in excess of 36:1 (diamond:silicon). We use these masks to produce a variety of diamond photonic devices.