Shining Diamond: from Micro- and Nano-Engineering to Quantum Photonics

The discovery of room-temperature single photon emission from color centers in diamond has in recent years boosted research interest in this renowned material in photonics and quantum community and beyond. Following understanding some basic principles of how the color centers work, new challenges arose: designing and fabricating real devices that leverage the unrivaled properties that diamond possesses. Due to this material's extreme physical hardness and its chemical resistance to etchants, the established semiconductor technologies cannot straightforwardly answer to the call for scalable and reliable fabrication of micro- and nano-photonic devices in single crystal diamond. In this thesis, we first demonstrate an unconventional polishing protocol with ion beam etching, which makes possible wafer-scale fine finishing of diamond substrates, the starting point for any subsequent processing. Following this we present the experimental observation of self-organized nanotextures on diamond induced by ion beam irradiation, a lithography-free approach for nanoengineering periodic structures. Regarding device fabrication, we obtained free-standing micro- and nano-photonic structures using angled reactive ion etching, facilitated by a novel and reproducible Faraday cage design. We also propose possible designs to interconnect individual components in hope of realizing a photonic integrated circuit in the future. Last but not least, we present spectroscopic characterization of single and ensemble color centers either grown by microwave plasma chemical vapor deposition, or fabricated by ion implantation with subsequent high-temperature annealing, which are the fundamental building blocks for quantum applications. Photoluminescence spectra that, to our knowledge, are not seen in literature were recorded for ensemble silicon-vacancy centers at cryogenic temperature, signifying potentially unknown mechanism for tuning the optical transitions, and unexplored possibilities with this exciting material platform for quantum technologies.