Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Photoinduced Modification of Second Harmonic Generation in Diamond Cavities

Sigurd Flågan, Joe Itoi, Prasoon Kumar Shandilya, Elham Zohari, Vinaya K. Kavatamane, Joseph E. Losby, Paul E. Barclay

Published Jan 1, 2024• 0 citations
Publisher

Abstract

We demonstrate cavity-enhanced second-harmonic generation from a diamond microdisk. By performing multicolor illumination, we show that optical manipulation of nitrogen-vacancy centers strongly affects the second-harmonic signal, indicating a difference in χ(2) between two possible electronic configurations.
DOI
10.1364/cleo_fs.2024.ff2n.5

Related papers

Photoinduced Modification of SHG Mediated by NV Centers in a Diamond Microcavity

Sigurd Flågan, Joe Itoi, Prasoon Kumar Shandilya +4 more

We demonstrate cavity-enhanced second-harmonic generation from a diamond microdisk. We further show that multicolor excitation of nitrogen-vacancy centers strongly affects the observed second-harmonic signal, indicating a difference in χ(2) between the two possible charge-states.

Quantum 2.0 Conference and Exhibition•Jan 1, 2024•0 citations

Cavity-enhanced second- and third-harmonic generation from a diamond microdisk

Sigurd Flågan, Joe Itoi, Prasoon Kumar Shandilya +1 more

We demonstrate cavity-enhanced second- and third-harmonic generation from a diamond microdisk containing nitrogen-vacancy centers. The photon emission follows a clear dependency with detuning of both the pump and emission modes, indicating a doubly-resonant configuration.

•Jan 1, 2023•0 citations

Novel nonlinear optics in diamond micro- and nano-cavities

Sigurd Flågan, Joe Itoi, Elham Zohari +7 more

Diamond constitutes a promising material platform for a myriad of photonic applications. In this work, we demonstrate several novel nonlinear optical phenomena in fibre-taper coupled diamond micro and nanocavities. Central to these observations are ensembles of nitrogen-vacancy (NV) centres native to the diamond devices. We first show photoinduced modifications of second-harmonic generation (SHG) from a microdisk, and demonstrate, for the first time, that the strength of the SHG strongly depends on the charge state of the NV centres. Illuminating the microdisk with a green laser quenches the SHG signal. Removing the green laser recovers the original SHG signal, allowing for deterministic optical switching of the device’s χ(2). We next show strong photorefractive blue-shifting of the resonance frequency in a diamond photonic crystal cavity. The total frequency shift exceeds the intrinsic linewidth, corresponding to a fractional change in refractive index of ∼ −10−4.

Integrated Optics: Design, Devices, Systems, and Applications•Jun 5, 2025•0 citations

Nonlinear Optics in a Diamond Micro- and Nano-Cavities

Sigurd Flågan, Joe Itoi, Prasoon Kumar Shandilya +7 more

Resonant recirculation of light in optical microcavities can greatly enhance light-matter interactions. In this work, we demonstrate cavity-enhanced second-harmonic and third-harmonic generation from a single-crystal diamond microdisk. The presence of crystal defects – here nitrogen-vacancy centers – breaks the inversion symmetry of the diamond crystal, allowing for observation of the otherwise forbidden second-harmonic generation. We further show that the photon emission follows a clear dependency with cavity detuning of both the pump and emission modes, a clear indication of a doubly-resonant configuration.

Photonics North (PN)•Jun 12, 2023•1 citation

Cavity-enhanced second- and third-harmonic generation from a diamond microdisk

Sigurd Flågan, Joe Itoi, Prasoon Kumar Shandilya +4 more

We demonstrate that defects in diamond break inversion symmetry, by observing cavity-enhanced second-harmonic generation – an otherwise forbidden process. The observed second- and third-harmonic emission follows a clear dependency with cavity de-tuning, indicating a doubly-resonant configuration.

Nonlinear Optics•Jan 1, 2023•0 citations

Optical Switching of χ ( 2 ) in Diamond Photonics

Sigurd Flågan, Joe Itoi, Prasoon Kumar Shandilya +4 more

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 nonzero second-order susceptibility, χ^{(2)}≠0, requires symmetry breaking. In this Letter, we use a nanoscale cavity to demonstrate second-harmonic generation (SHG) in diamond, and demonstrate, for the first time, that the magnitude of diamond's effective χ^{(2)} strongly depends on the electronic configuration of defects in the diamond crystal, such as nitrogen-vacancy centers. The modification of χ^{(2)} arises from photoionization 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 χ^{(2)}. Optical control of χ^{(2)} by defect engineering opens the door for second-order nonlinear processes in diamond.

arXiv:2412.06792•Physical Review Letters•Oct 28, 2025•3 citations
Diamond constitutes a promising material platform for a myriad of photonic applications. In this work, we demonstrate several novel nonlinear optical phenomena in fibre-taper coupled diamond micro and nanocavities. Central to these observations are ensembles of nitrogen-vacancy (NV) centres native to the diamond devices. We first show photoinduced modifications of second-harmonic generation (SHG) from a microdisk, and demonstrate, for the first time, that the strength of the SHG strongly depends on the charge state of the NV centres. Illuminating the microdisk with a green laser quenches the SHG signal. Removing the green laser recovers the original SHG signal, allowing for deterministic optical switching of the device’s χ(2). We next show strong photorefractive blue-shifting of the resonance frequency in a diamond photonic crystal cavity. The total frequency shift exceeds the intrinsic linewidth, corresponding to a fractional change in refractive index of ∼ −10−4.
Resonant recirculation of light in optical microcavities can greatly enhance light-matter interactions. In this work, we demonstrate cavity-enhanced second-harmonic and third-harmonic generation from a single-crystal diamond microdisk. The presence of crystal defects – here nitrogen-vacancy centers – breaks the inversion symmetry of the diamond crystal, allowing for observation of the otherwise forbidden second-harmonic generation. We further show that the photon emission follows a clear dependency with cavity detuning of both the pump and emission modes, a clear indication of a doubly-resonant configuration.
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 nonzero second-order susceptibility, χ^{(2)}≠0, requires symmetry breaking. In this Letter, we use a nanoscale cavity to demonstrate second-harmonic generation (SHG) in diamond, and demonstrate, for the first time, that the magnitude of diamond's effective χ^{(2)} strongly depends on the electronic configuration of defects in the diamond crystal, such as nitrogen-vacancy centers. The modification of χ^{(2)} arises from photoionization 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 χ^{(2)}. Optical control of χ^{(2)} by defect engineering opens the door for second-order nonlinear processes in diamond.