“With our diamond processing capabilities, we are establishing a technology platform that brings together precise nanofabrication and quantum optical functionality,” Prof. Dr. Tim Schröder, head of the Joint Lab Diamond Nanophotonics, said.
The Ferdinand-Braun-Institut (FBH) is rolling out a diamond processing platform designed to develop nanoscale components for quantum communication, sensing, and information processing. Customers can commission surface preparation, ion implantation to create color centers, and nanoscale pillar fabrication separately or in combination.
Defects in the diamond crystal lattice, known as color centers, behave like individual atoms. Their discrete spin states can be addressed through optical transitions, making them promising building blocks for quantum memories and light sources for quantum communication and sensing. Translating these properties into functional devices requires diamond itself to be processed with high precision.
At FBH, the Joint Lab Diamond Nanophotonics with Humboldt-Universität zu Berlin combines semiconductor process technology with expertise in quantum optics and solid-state nanosystems. Schröder said this allows them to develop and refine processes for different color centers and make them available for research and application-oriented development.
FBH offers three complementary processing steps. First, plasma etching prepares the diamond surface for further processing by removing the strain and damage near the surface left by mechanical polishing, which can introduce unwanted noise in quantum applications.
Using oxygen- and chlorine-based plasma etching, FBH can remove up to 20 micrometers of material while maintaining a surface roughness of around 0.5 nanometers rms. Next, selected ions can be implanted into the diamond to create color centers.
FBH can introduce different elements, including carbon, nitrogen, silicon, germanium, and tin, to create specific color centers. Implantation into high-purity diamond substrates helps achieve color centers with low noise and good coherence.
Finally, FBH can structure the diamond into nanoscale pillars. These structures can contain individual color centers and enhance the collection of the photons they emit, improving the efficiency of single-photon sources. They can also be used for quantum sensing and communication. Electron-beam lithography provides the flexibility to tailor the geometry of the nanostructures to specific applications.
The processing platform builds on years of research into defect centers in diamond and FBH’s established expertise in nanofabrication. Its goal is to achieve reproducible, scalable processes and ultimately combine diamond nanostructures with photonic circuits.
In a study published in Physical Review X, researchers demonstrated nitrogen-vacancy centers in diamond nanopillars with narrow optical linewidths, including lifetime-limited linewidths measured on a one-second timescale and an inhomogeneous linewidth of 150 MHz. In further studies, collaborators investigated the optical and quantum properties of color centers implanted at FBH, as detailed on the FBH diamond processing service page.
