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

arXiv:1611.07894 · Physical Review Applied

Enhanced Resolution in Nanoscale NMR via Quantum Sensing with Pulses of Finite Duration

J. E. Lang, J. Casanova, Z.-Y. Wang, Martin Bodo Plenio, T. S. Monteiro

Published May 15, 2017• 22 citations
arXivHTMLPDF

Abstract

Nanoscale sensing experiments based on defects in diamond are at the forefront of quantum-technology research. Nanoscale NMR and MRI employ microwave pulses to decouple the quantum sensor from sources of decoherence, and to enhance weak signals from a single nuclear spin. Here finite pulse duration has been largely considered a source of experimental error, but the authors see it differently: A quantum model shows that seemingly spurious signals due to nonzero pulse width are predictable, allowing experimental protocols for either their full suppression, or their exploitation to increase resolution.

DOI
10.1103/physrevapplied.7.054009

Related papers

Nonvanishing effect of detuning errors in dynamical-decoupling-based quantum sensing experiments

J. E. Lang, Trisha Madhavan, Jean‐Philippe Tetienne +6 more

Characteristic dips appear in the coherence traces of a probe qubit when dynamical decoupling (DD) is applied in synchrony with the precession of target nuclear spins, forming the basis for nanoscale nuclear magnetic resonance (NMR). The frequency of the microwave control pulses is chosen to match the qubit transition but this can be detuned from resonance by experimental errors, hyperfine coupling intrinsic to the qubit, or inhomogeneous broadening. The detuning acts as an additional static field which is generally assumed to be completely removed in Hahn echo and DD experiments. Here we demonstrate that this is not the case in the presence of finite pulse-durations, where a detuning can drastically alter the coherence response of the probe qubit, with important implications for sensing applications. Using the electronic spin associated with a nitrogen-vacancy center in diamond as a test qubit system, we analytically and experimentally study the qubit coherence response under CPMG and XY8 dynamical decoupling control schemes in the presence of finite pulse-durations and static detunings. Most striking is the splitting of the NMR resonance under CPMG, whereas under XY8 the amplitude of the NMR signal is modulated. Our work shows that the detuning error must not be neglected when extracting data from quantum sensor coherence traces.

arXiv:1809.03234•Physical Review A•Jan 9, 2019•19 citations

Dynamical decoupling methods in nanoscale NMR

C. Munuera-Javaloy, R. Puebla, J. Casanova

Nuclear magnetic resonance (NMR) schemes can be applied to micron-, and nanometer-sized samples by the aid of quantum sensors such as nitrogen vacancy (NV) color centers in diamond. These minute devices allow for magnetometry of nuclear spin ensembles with high spatial and frequency resolution at ambient conditions, thus having a clear impact in different areas such as chemistry, biology, medicine, and material sciences. In practice, NV quantum sensors are driven by microwave (MW) control fields with a twofold objective: On the one hand, MW fields bridge the energy gap between NV and nearby nuclei which enables a coherent and selective coupling among them while, on the other hand, MW fields remove environmental noise on the NV leading to enhanced interrogation time. In this work we review distinct MW radiation patterns, or dynamical decoupling techniques, for nanoscale NMR applications.

arXiv:2104.10617•Europhysics Letters (EPL)•May 1, 2021•11 citations

Nanoscale magnetic spectroscopy with colour centres in diamond

Simon Schmitt

Quantum technologies are expected to significantly change our world in the next decades and the possible applications are diverse – ranging from quantum computation and encryption to metrology with unprecedented sensitivity. This thesis focuses on quantum sensing and imaging based on single nitrogen-vacancy (NV) centres in diamond to measure magnetic fields. Its electronic spin qualifies this point defect as a highly sensitive quantum sensor and its atomic size offers nanoscale spatial resolution. The simple optical initialisation and readout, together with the relatively long coherence time at ambient conditions, make NV centres promising candidates for biological applications and in particular for nuclear magnetic resonance (NMR) on the nanoscale. Recording the spectral information on the nanoscale allows to determine the structure of single or just a few molecules. However, the current main problems and challenges include insufficient spectral resolution, artificial signals and overall poor performance. In this thesis new spectroscopic techniques which tackle these issues are presented. First, it is shown that by randomisation of control pulse phases spurious harmonic signals can be suppressed, which otherwise complicate spectrum interpretation and can lead to false signal identification. At the same time the effects of pulse imperfections are mitigated. Furthermore, a protocol allowing to measure with a coherence independent spectral resolution is presented. It is demonstrated that linewidths below 1mHz are possible, which is an improvement of more than seven orders of magnitude compared to traditional methods. Due to its simple implementation, the protocol is relevant for many applications. Initially developed to measure signals oscillating up to several megahertz, it is further shown that modifications allow to extend the frequency range into the gigahertz domain. Finally, quantum frequency discrimination with the task to differentiate between two frequency distributions using a quantum sensor is analysed. An optimised protocol is introduced and the influences of different readout strategies are discussed with respect to the probability to make an incorrect decision. These findings are useful for diagnostic tests in NMR.

•Jan 1, 2020•0 citations

Submillihertz magnetic spectroscopy performed with a nanoscale quantum sensor

Simon Schmitt, Tuvia Gefen, Felix M. Stürner +13 more

Enhancing quantum sensing The quantum properties of the nitrogen vacancy (NV) defect in diamond can be used as an atomic compass needle that is sensitive to tiny variations in magnetic field. Schmitt et al. and Boss et al. successfully enhanced this sensitivity by several orders of magnitude (see the Perspective by Jordan). They applied a sequence of pulses to the NV center, the timing of which was set by and compared with a highly stable oscillator. This allowed them to measure the frequency of an oscillating magnetic field (megahertz bandwidth) with submillihertz resolution. Such enhanced precision measurement could be applied, for example, to improve nuclear magnetic resonance-based imaging protocols of single molecules. Science , this issue p. 832 , p. 837 ; see also p. 802

arXiv:1706.02103•Science•May 25, 2017•362 citations

Enhancing quantum sensing sensitivity by a quantum memory

Sebastian Zaiser, Torsten Rendler, Ingmar Jakobi +7 more

In quantum sensing, precision is typically limited by the maximum time interval over which phase can be accumulated. Memories have been used to enhance this time interval beyond the coherence lifetime and thus gain precision. Here, we demonstrate that by using a quantum memory an increased sensitivity can also be achieved. To this end, we use entanglement in a hybrid spin system comprising a sensing and a memory qubit associated with a single nitrogen-vacancy centre in diamond. With the memory we retain the full quantum state even after coherence decay of the sensor, which enables coherent interaction with distinct weakly coupled nuclear spin qubits. We benchmark the performance of our hybrid quantum system against use of the sensing qubit alone by gradually increasing the entanglement of sensor and memory. We further apply this quantum sensor-memory pair for high-resolution NMR spectroscopy of single (13)C nuclear spins.

Nature Communications•Aug 10, 2016•180 citations

Quantum biosensing enabled by diamond colour centres

Fedor Jelezko

Synthetic diamond has recently emerged as a candidate material for a number of quantum applications, including quantum information processing and quantum sensing. In this talk, I will show how single nitrogen-vacancy (NV) color centers can be created near the diamond surface and used as nanoscale sensors of electric and magnetic fields. I will also demonstrate novel dynamical decoupling techniques allowing to improve the sensitivity of diamond quantum sensors and discuss applications of small-scale quantum registers for nanoscale NMR. Applications of NV centers for hyperpolarisation of nuclear spins and application of optical spin polarization in MRI will be presented.

Quantum Effects and Measurement Techniques in Biology and Biophotonics•Mar 4, 2026•0 citations
Nanoscale sensing experiments based on defects in diamond are at the forefront of quantum-technology research. Nanoscale NMR and MRI employ microwave pulses to decouple the quantum sensor from sources of decoherence, and to enhance weak signals from a single nuclear spin. Here finite pulse duration has been largely considered a source of experimental error, but the authors see it differently: A quantum model shows that seemingly spurious signals due to nonzero pulse width are predictable, allowing experimental protocols for either their full suppression, or their exploitation to increase resolution.
Characteristic dips appear in the coherence traces of a probe qubit when dynamical decoupling (DD) is applied in synchrony with the precession of target nuclear spins, forming the basis for nanoscale nuclear magnetic resonance (NMR). The frequency of the microwave control pulses is chosen to match the qubit transition but this can be detuned from resonance by experimental errors, hyperfine coupling intrinsic to the qubit, or inhomogeneous broadening. The detuning acts as an additional static field which is generally assumed to be completely removed in Hahn echo and DD experiments. Here we demonstrate that this is not the case in the presence of finite pulse-durations, where a detuning can drastically alter the coherence response of the probe qubit, with important implications for sensing applications. Using the electronic spin associated with a nitrogen-vacancy center in diamond as a test qubit system, we analytically and experimentally study the qubit coherence response under CPMG and XY8 dynamical decoupling control schemes in the presence of finite pulse-durations and static detunings. Most striking is the splitting of the NMR resonance under CPMG, whereas under XY8 the amplitude of the NMR signal is modulated. Our work shows that the detuning error must not be neglected when extracting data from quantum sensor coherence traces.
Nuclear magnetic resonance (NMR) schemes can be applied to micron-, and nanometer-sized samples by the aid of quantum sensors such as nitrogen vacancy (NV) color centers in diamond. These minute devices allow for magnetometry of nuclear spin ensembles with high spatial and frequency resolution at ambient conditions, thus having a clear impact in different areas such as chemistry, biology, medicine, and material sciences. In practice, NV quantum sensors are driven by microwave (MW) control fields with a twofold objective: On the one hand, MW fields bridge the energy gap between NV and nearby nuclei which enables a coherent and selective coupling among them while, on the other hand, MW fields remove environmental noise on the NV leading to enhanced interrogation time. In this work we review distinct MW radiation patterns, or dynamical decoupling techniques, for nanoscale NMR applications.
Quantum technologies are expected to significantly change our world in the next decades and the possible applications are diverse – ranging from quantum computation and encryption to metrology with unprecedented sensitivity. This thesis focuses on quantum sensing and imaging based on single nitrogen-vacancy (NV) centres in diamond to measure magnetic fields. Its electronic spin qualifies this point defect as a highly sensitive quantum sensor and its atomic size offers nanoscale spatial resolution. The simple optical initialisation and readout, together with the relatively long coherence time at ambient conditions, make NV centres promising candidates for biological applications and in particular for nuclear magnetic resonance (NMR) on the nanoscale. Recording the spectral information on the nanoscale allows to determine the structure of single or just a few molecules. However, the current main problems and challenges include insufficient spectral resolution, artificial signals and overall poor performance. In this thesis new spectroscopic techniques which tackle these issues are presented. First, it is shown that by randomisation of control pulse phases spurious harmonic signals can be suppressed, which otherwise complicate spectrum interpretation and can lead to false signal identification. At the same time the effects of pulse imperfections are mitigated. Furthermore, a protocol allowing to measure with a coherence independent spectral resolution is presented. It is demonstrated that linewidths below 1mHz are possible, which is an improvement of more than seven orders of magnitude compared to traditional methods. Due to its simple implementation, the protocol is relevant for many applications. Initially developed to measure signals oscillating up to several megahertz, it is further shown that modifications allow to extend the frequency range into the gigahertz domain. Finally, quantum frequency discrimination with the task to differentiate between two frequency distributions using a quantum sensor is analysed. An optimised protocol is introduced and the influences of different readout strategies are discussed with respect to the probability to make an incorrect decision. These findings are useful for diagnostic tests in NMR.
Enhancing quantum sensing The quantum properties of the nitrogen vacancy (NV) defect in diamond can be used as an atomic compass needle that is sensitive to tiny variations in magnetic field. Schmitt et al. and Boss et al. successfully enhanced this sensitivity by several orders of magnitude (see the Perspective by Jordan). They applied a sequence of pulses to the NV center, the timing of which was set by and compared with a highly stable oscillator. This allowed them to measure the frequency of an oscillating magnetic field (megahertz bandwidth) with submillihertz resolution. Such enhanced precision measurement could be applied, for example, to improve nuclear magnetic resonance-based imaging protocols of single molecules. Science , this issue p. 832 , p. 837 ; see also p. 802
In quantum sensing, precision is typically limited by the maximum time interval over which phase can be accumulated. Memories have been used to enhance this time interval beyond the coherence lifetime and thus gain precision. Here, we demonstrate that by using a quantum memory an increased sensitivity can also be achieved. To this end, we use entanglement in a hybrid spin system comprising a sensing and a memory qubit associated with a single nitrogen-vacancy centre in diamond. With the memory we retain the full quantum state even after coherence decay of the sensor, which enables coherent interaction with distinct weakly coupled nuclear spin qubits. We benchmark the performance of our hybrid quantum system against use of the sensing qubit alone by gradually increasing the entanglement of sensor and memory. We further apply this quantum sensor-memory pair for high-resolution NMR spectroscopy of single (13)C nuclear spins.
Synthetic diamond has recently emerged as a candidate material for a number of quantum applications, including quantum information processing and quantum sensing. In this talk, I will show how single nitrogen-vacancy (NV) color centers can be created near the diamond surface and used as nanoscale sensors of electric and magnetic fields. I will also demonstrate novel dynamical decoupling techniques allowing to improve the sensitivity of diamond quantum sensors and discuss applications of small-scale quantum registers for nanoscale NMR. Applications of NV centers for hyperpolarisation of nuclear spins and application of optical spin polarization in MRI will be presented.