Hybrid light collection

Diamond can host a variety of point defects, some of which are already well known and utilized for quantum applications, others are just coming up as new promising candidates. As quantum applications often require the interaction of a light field with a single or only a few emitters at the same time, it is crucial to increase the number of collected photons, as well as to tailor the interaction with the light field. After a brief discussion on how an increase of the detected photons would affect different quantum applications, two different hybrid approaches, including their respective experimental implementation, are discussed in detail. First, the concept of a bullseye antenna is discussed, which mainly focuses on a simple and robust way to enhance the collection via free-space optics and into low collection angles. With this structure a collection efficiency of up to 85% into an NA of 0.9 could be realized. The second structure goes toward a fiber-coupled device, in order to prototype a fully integrated single-photon source. Here a single defect center is coupled to an on-chip silica waveguide, and its emitted photons are routed to single-mode fibers.