Color-Center-Compatible Freestanding Diamond Directional Couplers for Quantum Photonics
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 λ0≈ 637 nm yield a mean coupling ratio of Cmeas=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.
Versions
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BibTeX
@misc{sauerzapf2026colorcentercompatible,
title = {{Color-Center-Compatible Freestanding Diamond Directional Couplers for Quantum Photonics}},
author = {Colin Sauerzapf and Tom Jäger and Jonathan Enßlin and Oliver von Berg and Vladislav Bushmakin and Roman Kolesov and Rainer Stöhr and Vadim Vorobyov and Jörg Wrachtrup},
howpublished = {arXiv},
year = {2026},
month = jun,
doi = {10.48550/arxiv.2606.24576},
eprint = {2606.24576},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.24576},
}
RIS
TY - UNPB
TI - Color-Center-Compatible Freestanding Diamond Directional Couplers for Quantum Photonics
AU - Colin Sauerzapf
AU - Tom Jäger
AU - Jonathan Enßlin
AU - Oliver von Berg
AU - Vladislav Bushmakin
AU - Roman Kolesov
AU - Rainer Stöhr
AU - Vadim Vorobyov
AU - Jörg Wrachtrup
PY - 2026
DA - 2026/06/24
PB - arXiv
DO - 10.48550/arxiv.2606.24576
UR - https://arxiv.org/abs/2606.24576
AB - 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≈ 637 nm yield a mean coupling ratio of C^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.
ER -