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arXiv · 2603.11367

Saturable absorption in defect-rich diamond nanophotonics

Christopher Coutts·Nicholas J. Sorensen·Elham Zohari·Sean McNaney·Sigurd Flågan·Paul E. Barclay
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Abstract

Diamond is a leading quantum photonics platform due to its ability to host qubits based on crystal defects such as nitrogen-vacancy centres. Fabricating nanophotonic devices from defect-rich diamond, which underpins many quantum sensing technologies, promises enhanced performance and integrability of diamond quantum sensors. Here we demonstrate microdisk cavities fabricated from defect-rich diamond that support optical modes with high quality factor (${Q}\sim7\times10^4$ at $1042\,$nm) and show that they exhibit saturable absorption. Power-dependent spectroscopy measurements spanning 979$\,$nm to 1604$\,$nm are used to observe intensity-dependent cavity loss and extract wavelength-dependent absorption coefficients and saturation intensities. At 1047$\,$nm, we observe saturation and measure a saturation intensity of $2.1\,(8)\,$MW/cm$^2$ and an absorption coefficient of $0.53\,(2)\,$cm$^{-1}$. These results provide insight into defect-mediated optical loss in diamond nanophotonics and suggest strategies to harness defect-induced nonlinearities in future diamond photonic devices.

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Christopher Coutts, Nicholas J. Sorensen, Elham Zohari, Sean McNaney, Sigurd Flågan, Paul E. Barclay. 2026-03-11. Saturable absorption in defect-rich diamond nanophotonics. https://doi.org/10.1364/optica.597613

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