The remarkable optical characteristics of diamond, along with its various intrinsic color centers that possess long coherence times, have fostered a vibrant and expanding research community in recent decades. Diamond-based integrated photonic circuits (PIC) are increasingly contributing to advancements in quantum sensing, computing, and communication technologies. Although significant strides have been made in device fabrication demonstrations, challenges related to reproducibility and scalability persist. We investigate the development of lateral wave guide structures on diverse diamond substrates, with an emphasis on the integration of color centers such as the Nitrogen Vacancy (NV) and Silicon Vacancy (SiV) defects. We carried out electric field simulations to optimize device performance. Optical microring resonators, waveguides, and photonic crystal cavities were processed employing electron-beam lithography, metal/dielectric mask deposition, and oxygen dry etching via “Inductively coupled plasma” (ICP). Undercutting was accomplished with means of Faraday-Cage-Angled-Etching (FCAE) as well as quasi-isotropic etching, and we evaluate the pros and cons of these techniques. The devices were analyzed using micro-photoluminescence, revealing resonant cavity modes within the large phonon sidebands of the NV emission spectrum. Furthermore, hetero integration of the photonic integrated circuits was tested with the aid of micromanipulators.

Dr. Christian Giese studied physics at the university of Freiburg where he acquired his P.h.D. working of quantum optics and atomic physics in 2012. He then started his career at Zeiss SMT Oberkochen focusing on metrology of EUV optics for next generation EUV steppers. In 2013 he joined the technology department at the Fraunhofer IAF in Freiburg to develop cleanroom processes for diamond based devices. He holds a number of patents, is author or co-author of more than 40 peer-reviewed publications and leads the nanofabrication technology activities for NV-devices at IAF. Research interests: semiconductor technology development, electron beam lithography, laser ligthography, dry etching, diamond devices, color centres, optical metrology, photonic integrated circuits, quantum technology