Generating accurate tip angles for NMR outside the rotating-wave approximation

Bidinosti, Christopher; Tastevin, Geneviève; Nacher, Pierre-Jean

doi:10.1016/j.jmr.2022.107306

Cited by 2 publications

(1 citation statement)

References 43 publications

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“…We note that the phase of the driving field was shown to be important in the strong driving regime in NMR already more than five decades ago [36]. More recently, the phase's effect was shown in single solid-state qubit experiments [37,38] and in NMR [39]. However, the phase has not been discussed in the context of tilted drives or in combination with a DC offset.…”

Section: Resonant Offset-sine Driving Pulsesmentioning

confidence: 91%

Coherent manipulation of nuclear spins in the strong driving regime

Yudilevich,

Salhov,

Schaefer

et al. 2023

New J. Phys.

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Spin-based quantum information processing makes extensive use of spin statemanipulation. This ranges from dynamical decoupling of nuclear spins inquantum sensing experiments to applying logical gates on qubits in a quantumprocessor. Fast manipulation of spin states is highly desirable for acceleratingexperiments, enhancing sensitivity, and applying elaborate pulse sequences. Strongdriving using intense radio-frequency (RF) fields can, therefore, facilitate fastmanipulation and enable broadband excitation of spin species.In this work, we present an antenna for strong driving in quantum sensingexperiments and theoretically address challenges of the strong driving regime. First,we designed and implemented a micron-scale planar spiral RF antenna capable ofdelivering intense fields to a sample. The planar antenna is tailored for quantumsensing experiments using the diamond’s nitrogen-vacancy (NV) center and should beapplicable to other solid-state defects. The antenna has a broad bandwidth of 22 MHz,is compatible with scanning probes, and is suitable for cryogenic and ultrahigh vacuumconditions. We measure the magnetic field induced by the antenna and estimate a field-to-current ratio of 113±16 G/A, representing a six-fold increase in efficiency comparedto the state-of-the-art, crucial for cryogenic experiments. We demonstrate the antennaby driving Rabi oscillations in 1H spins of an organic sample on the diamond surfaceand measure 1H Rabi frequencies of over 500 kHz, i.e., π-pulses shorter than 1 μs –faster than previously reported in NV-based nuclear magnetic resonance (NMR).Finally, we discuss the implications of driving spins with a field tilted from thetransverse plane in a regime where the driving amplitude is comparable to the spin statesplitting, such that the rotating wave approximation does not describe thedynamics well. We present a simple recipe to optimize pulse fidelity in this regimebased on a phase and offset-shifted sine drive, which may be optimized in situ withoutnumerical optimization procedures or precise modeling of the experiment. We considerthis approach in a range of driving amplitudes and show that it is particularly efficientin the case of a tilted driving field.The results presented here constitute a foundation for implementing fast nuclearspin control in various systems.

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Section: Resonant Offset-sine Driving Pulsesmentioning

confidence: 91%

Coherent manipulation of nuclear spins in the strong driving regime

Yudilevich,

Salhov,

Schaefer

et al. 2023

New J. Phys.

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Bloch–Siegert Effect for Surface Nuclear Magnetic Resonance Sounding Experiments in the Unsaturated Zone

2023

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The Bloch–Siegert effect is relevant for NMR experiments where components of the excitation pulse other than the circularly polarized component have an influence on the evolution of the magnetization of the spin system under consideration. For linearly polarized excitation fields this happens at amplitudes higher than roughly one tenth of the magnitude of the static magnetic field. Since surface nuclear magnetic resonance (SNMR) experiments, also called magnetic-resonance-soundings (MRS), are conducted in the relatively low local field of the earth, the Bloch–Siegert effect can quickly become relevant. This is especially the case for SNMR experiments in the unsaturated zone, where due to short relaxation times fast pulses of high intensity must be used. To describe the Bloch–Siegert effect, we use the average Hamiltonian approximation obtained by the Magnus expansion of up to fifth order, as well as the solution of the Bloch equations. The results of these approximations are tested against the Bloch simulations and it is shown that they are only valid for limited ranges of the excitation field amplitude. The influence of the Bloch–Siegert effect on sensitivity kernels is described and verified with experimental data obtained with a small scale SNMR sensor on water containers.

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Generating accurate tip angles for NMR outside the rotating-wave approximation

Cited by 2 publications

References 43 publications

Coherent manipulation of nuclear spins in the strong driving regime

Coherent manipulation of nuclear spins in the strong driving regime

Bloch–Siegert Effect for Surface Nuclear Magnetic Resonance Sounding Experiments in the Unsaturated Zone

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