Nicholas R. Jungwirth

Mechanical spin control of nitrogen-vacancy centers in diamond.

We demonstrate direct coupling between phonons and diamond nitrogen-vacancy (NV) center spins by driving spin transitions with mechanically generated harmonic strain at room temperature. The amplitude of the mechanically driven spin signal varies with the spatial periodicity of the stress standing wave within the diamond substrate, verifying that we drive NV center spins mechanically. These spin-phonon interactions could offer a route to quantum spin control of magnetically forbidden transitions, which would enhance NV-based quantum metrology, grant access to direct transitions between all of the spin-1 quantum states of the NV center, and provide a platform to study spin-phonon interactions at the level of a few interacting spins.

Temperature Dependence of Wavelength Selectable Zero-Phonon Emission from Single Defects in Hexagonal Boron Nitride

We investigate the distribution and temperature-dependent optical properties of sharp, zero-phonon emission from defect-based single photon sources in multilayer hexagonal boron nitride (h-BN) flakes. We observe sharp emission lines from optically active defects distributed across an energy range that exceeds 500 meV. Spectrally resolved photon-correlation measurements verify single photon emission, even when multiple emission lines are simultaneously excited within the same h-BN flake. We also present a detailed study of the temperature-dependent line width, spectral energy shift, and intensity for two different zero-phonon lines centered at 575 and 682 nm, which reveals a nearly identical temperature dependence despite a large difference in transition energy. Our temperature-dependent results are well described by a lattice vibration model that considers piezoelectric coupling to in-plane phonons. Finally, polarization spectroscopy measurements suggest that whereas the 575 nm emission line is directly excited by 532 nm excitation, the 682 nm line is excited indirectly.

Coherent control of a nitrogen-vacancy center spin ensemble with a diamond mechanical resonator

Coherent control of the nitrogen-vacancy (NV) center in diamonds triplet spin state has traditionally been accomplished with resonant ac magnetic fields under the constraint of the magnetic dipole selection rule, which forbids direct control of the

A single-molecule approach to ZnO defect studies: Single photons and single defects

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Polarization Spectroscopy of Defect-Based Single Photon Sources in ZnO

spin transition. We show that high-frequency stress resonant with the spin state splitting can coherently control NV center spins within this subspace. Using a bulk-mode mechanical microresonator fabricated from single-crystal diamond, we apply intense ac stress to the diamond substrate and observe mechanically driven Rabi oscillations between the

Optical Absorption and Emission Mechanisms of Single Defects in Hexagonal Boron Nitride

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Chemical Vapor Deposition Growth of Large Single-Crystal Mono-, Bi-, Tri-Layer Hexagonal Boron Nitride and Their Interlayer Stacking

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Single Quantum Defects in h-BN and ZnO

states of an NV center spin ensemble. Additionally, we measure the inhomogeneous spin dephasing time (

Polarization spectroscopy of defect-based single photon sources in ZnO

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