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arXiv · 2412.06792

Optical Switching of $\chi^{(2)}$ in Diamond Photonics

Sigurd Flågan·Joe Itoi·Prasoon K. Shandilya·Vinaya K. Kavatamane·Matthew Mitchell·David P. Lake·Paul E. Barclay
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Abstract

Diamond's unique physical properties make it a versatile material for a wide range of nonlinear and quantum photonic technologies. However, unlocking diamond's full potential as a nonlinear photonic material with non-zero second-order susceptibility $\chi^{(2)}\neq0$ requires symmetry breaking. In this work, we use a nanoscale cavity to demonstrate second-harmonic generation (SHG) in diamond, and demonstrate, for the first time, that the magnitude of the diamond's effective $\chi^{(2)}$ strongly depends on the electronic configuration of defects in the diamond crystal, such as nitrogen-vacancy centres. The modification of $\chi^{(2)}$ arises from photoionisation from the negative to neutral charge-state, and is manifested by quenching of SHG upon green illumination. Toggling the green illumination allows for optical switching of the device's $\chi^{(2)}$. Optical control of $\chi^{(2)}$ by defect engineering opens the door for second-order nonlinear processes in diamond.

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Sigurd Flågan, Joe Itoi, Prasoon K. Shandilya, Vinaya K. Kavatamane, Matthew Mitchell, David P. Lake, Paul E. Barclay. 2024-11-22. Optical Switching of $\chi^{(2)}$ in Diamond Photonics. https://doi.org/10.1103/yx3z-cr5v

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