Saturable absorption in defect-rich diamond nanophotonics

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 ($Q\sim 7\times 10^4$ at $1042$nm) and show that they exhibit saturable absorption. Power-dependent spectroscopy measurements spanning 979nm to 1604nm are used to observe intensity-dependent cavity loss and extract wavelength-dependent absorption coefficients and saturation intensities. At 1047nm, 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.

20 pages, 12 figures

References in corpus (2)

• Optical Switching of $\ddot{I}{‡}^{(2)}$ in Diamond Photonics
• Nonlinear optical charge state switching and pumping to a diamond NV center dark state