Enhanced spectral density of a single germanium vacancy center in a nanodiamond by cavity integration
Florian Feuchtmayr, Robert Berghaus, Selene Sachero, Gregor Bayer, Niklas Lettner, Richard Waltrich, Patrick Maier, V. Agafonov, Alexander Kubanek
Abstract
Color centers in diamond, among them the negatively charged germanium vacancy (GeV−), are promising candidates for many applications of quantum optics, such as a quantum network. For efficient implementation, the optical transitions need to be coupled to a single optical mode. Here, we demonstrate the transfer of a nanodiamond containing a single ingrown GeV− center with excellent optical properties to an open Fabry–Pérot microcavity by nanomanipulation utilizing an atomic force microscope. Coupling of the GeV− defect to the cavity mode is achieved, while the optical resonator maintains a high finesse of F=7700, and a 48-fold spectral density enhancement is observed. This article demonstrates the integration of a GeV− defect with a Fabry–Pérot microcavity under ambient conditions with the potential to extend the experiments to cryogenic temperatures toward an efficient spin-photon platform.