{
  "abstract": "Freestanding all-diamond color-center photonics is a promising platform for optical integration of spin-based quantum defects. Within this geometry, we realize a key building block for quantum-network interconnects: a directional coupler that acts as an on-chip beam splitter. We design and simulate directional couplers with triangular cross sections using eigenmode and finite-difference time-domain simulations and target near-50:50 splitting at visible wavelengths. We fabricate the devices directly from bulk single-crystal diamond by angled oxygen reactive-ion-beam etching followed by a dry post-release hard-mask removal process. Room-temperature measurements at $λ_0\\approx 637 \\mathrm{nm}$ yield a mean coupling ratio of $C^\\mathrm{meas}=46(16) \\%$. Finally, we integrate SnV$^{-}$ centers into the nanophotonic structures and observe near-lifetime-limited optical linewidths and coherent optical Rabi oscillations without post-fabrication annealing, identifying the platform as a viable route towards integrated diamond quantum photonics.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.24576",
  "author_total": 9,
  "authors": [
    {
      "name": "Colin Sauerzapf"
    },
    {
      "name": "Tom Jäger"
    },
    {
      "name": "Jonathan Enßlin"
    },
    {
      "name": "Oliver von Berg"
    },
    {
      "name": "Vladislav Bushmakin"
    },
    {
      "name": "Roman Kolesov"
    },
    {
      "name": "Rainer Stöhr"
    },
    {
      "name": "Vadim Vorobyov"
    },
    {
      "name": "Jörg Wrachtrup"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/66rym2n8xg8x1.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.24576",
  "fulltext_url": null,
  "id": "66rym2n8xg8x1",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.24576",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.optics"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.24576",
  "pmcid": null,
  "pmid": null,
  "published": "2026-06-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/66rym2n8xg8x1.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:14Z",
      "native_id": "2606.24576",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.24576"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Color-Center-Compatible Freestanding Diamond Directional Couplers for Quantum Photonics",
  "title_text": "Color-Center-Compatible Freestanding Diamond Directional Couplers for Quantum Photonics",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:14Z",
  "url": "https://research.draconitic.com/paper/66rym2n8xg8x1",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1021/acsphotonics.6c01594",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}