Joint Lab Diamond Nanophotonics

The Joint Lab Diamond Nanophotonics (DNP) is researching novel concepts for guiding, capturing and manipulating light on the nano- and microscale. The aim is to achieve a controllable light-matter interaction in order to efficiently couple quantum memories in diamond to individual light particles (photons). These photons will then be efficiently coupled into optical fibers. To this end, the lab investigates and fabricates nanophotonic structures in diamond and combines them with other light-conducting materials that can already be reliably produced and processed today. In the long term, compact on-chip modules for quantum communication and computing are to be developed. Such photonic modules are a decisive step towards quantum information processing based on optically active solid-state materials. The basis for such information processing is formed by quantum networks derived from defect centers, which are scalably entangled at high rates. In a first step, the lab is working on demonstrating entanglement operations of diamond defect centers in integrated nanophotonic structures.

  • Scanning electron micrograph of a diamond photonic crystal nanocavity with integrated spin defect center.
    [+] Scanning electron micrograph of a diamond photonic crystal nanocavity with integrated spin defect center. Spin levels (green arrows: "spin-up" & "spin-down") are connected to optical transitions (red dashed lines). They can be used as quantum memory and, coupled to single photons (wiggly arrow), for the generation of spin-photon entanglement (dotted bow tie)
  • Scanning electron micrograph of a diamond microstructure.
    [+] Scanning electron micrograph of a diamond microstructure. The diamond-air interface is shaped like a parabolid (3 dimensions). The spin defect center (in the focal point of the parabolid) is coupled to single photons (red wiggly arrows) via optical transitions (red dashed lines). Photons are emitted into the far-field allowing to guide almost 50% of all emitted light into the collection lens.

Compared to other semiconductor technologies, nanostructuring of diamond has so far been scarcely researched worldwide. In order to use diamond-based technologies in an application-relevant way, comprehensive know-how in process technology must be established and combined with expertise in quantum optics with solid-state nanosystems.

The Joint Lab Diamond Nanophotonics relies on existing work with defect centers in diamond and the unique manufacturing processes at Ferdinand-Braun-Institut. As a result, an unprecedented level of structuring quality, reproducibility and scalability shall be achieved. In particular, diamond nanostructures and photonic circuits will be interconnected using new methods. Such a platform can then be used as a toolbox for the photonic integration of established and new defect centers in diamond.

This advanced platform will enable various applications: extremely bright quantum light sources integrated into a compact package for commercial applications, as well as highly efficient spin-photon interfaces used to demonstrate entanglement operations.

Publication

Noel H. Wan, Brendan J. Shields, Donggyu Kim, Sara Mouradian, Benjamin Lienhard, Michael Walsh, Hassaram Bakhru, Tim Schröder, Dirk Englund, “Efficient Extraction of Light from a Nitrogen-Vacancy Center in a Diamond Parabolic Reflector” Nano Lett. 2018 1852787-2793, (2018)