Optically detected nuclear magnetic resonance of carbon-13 in bulk diamond
Maxwell D. Aiello, Janis Smits, Yaser Silani, Andris Berzins, David Lidsky, Bryan A. Richards, Amilcar Jeronimo Perez, Chandrasekhar Ramanathan, Sebastián C. Carrasco, Jabir Chathanathil, Michael Goerz, Vladimir S. Malinovsky, Dmitry Budker, Sean Lourette, Andrey Jarmola, Victor M. Acosta
quant-phcond-mat.mes-hallphysics.atom-phphysics.ins-detphysics.opticsSubmitted Apr 30, 2026• Announced May 4, 2026• Revised Sep 26, 2026 (v3)
Precision measurements based on optically detected nuclear magnetic resonance offer exquisite sensitivity to absolute shifts in spin transition frequencies, with potential applications in fundamental physics experiments and inertial sensing. We investigate 13C nuclear spins in diamond as a candidate system for solid-state implementations, which hold the promise for high-fidelity readout of large numbers of coherent nuclear spins in millitesla or lower magnetic fields. We demonstrate a technique that allows for both optical polarization and readout of large ensembles of ~10^{16} polarized nuclear spins. Our method takes advantage of state-selective Landau-Zener transitions under microwave frequency sweeping, which bidirectionally transfer spin polarization between Nitrogen-Vacancy (NV) electron spins and remote 13C nuclear spins. Using natural isotopic abundance diamonds with nitrogen densities of ~0.5-10 ppm, we perform optically-detected 13C Ramsey spectroscopy and realize a nuclear-spin-dependent fluorescence contrast exceeding 0.5% peak-to-peak. We observe nuclear spin dephasing times T2*~2 ms that only modestly improve with homonuclear dipolar decoupling, indicating that they are limited by the longitudinal spin relaxation of nearby NV electron spins. We study the magnetic field dependence of the optical readout and find comparable contrast and dephasing times for magnetic fields in the range 8-20 mT. Our method can be interpreted as a type of repetitive readout, where each NV center optically reads out the spin state of ~10^2 nuclei before nuclear spins depolarize.
Precision measurements based on optically detected nuclear magnetic resonance offer exquisite sensitivity to absolute shifts in spin transition frequencies, with potential applications in fundamental physics experiments and inertial sensing. We investigate 13C nuclear spins in diamond as a candidate system for solid-state implementations, which hold the promise for high-fidelity readout of large numbers of coherent nuclear spins in millitesla or lower magnetic fields. We demonstrate a technique that allows for both optical polarization and readout of large ensembles of ~10^{16} polarized nuclear spins. Our method takes advantage of state-selective Landau-Zener transitions under microwave frequency sweeping, which bidirectionally transfer spin polarization between Nitrogen-Vacancy (NV) electron spins and remote 13C nuclear spins. Using natural isotopic abundance diamonds with nitrogen densities of ~0.5-10 ppm, we perform optically-detected 13C Ramsey spectroscopy and realize a nuclear-spin-dependent fluorescence contrast exceeding 0.5% peak-to-peak. We observe nuclear spin dephasing times T2*~2 ms that only modestly improve with homonuclear dipolar decoupling, indicating that they are limited by the longitudinal spin relaxation of nearby NV electron spins. We study the magnetic field dependence of the optical readout and find comparable contrast and dephasing times for magnetic fields in the range 8-20 mT. Our method can be interpreted as a type of repetitive readout, where each NV center optically reads out the spin state of ~10^2 nuclei before nuclear spins depolarize.
Nuclear spin ensembles in diamond are promising candidates for quantum sensing applications, including rotation sensing. Here we perform a characterization of the optically detected nuclear-spin transitions associated with the 14N nuclear spin within diamond nitrogen vacancy (NV) centers. We observe nuclear-spin-dependent fluorescence with the contrast of optically detected 14N nuclear Rabi oscillations comparable to that of the NV electron spin. Using Ramsey spectroscopy, we investigate the temperature and magnetic-field dependence of the nuclear spin transitions in the 77.5-420 K and 350-675 G range, respectively. The nuclear quadrupole coupling constant Q was found to vary with temperature T yielding d|Q|/dT=-35.0(2) Hz/K at T=297 K. The temperature and magnetic field dependencies reported here are important for quantum sensing applications such as rotation sensing and potentially for applications in quantum information processing.
Nitrogen vacancy (NV-) color centers in diamond are a prime candidate for use in quantum information devices, owing to their spin-1 ground state, straightforward optical initialization and readout, and long intrinsic coherence times in a room-temperature solid. While the 13C nuclear spin is often a dominant source of magnetic noise, we observe transitions between electron-nuclear hyperfine states of NV- centers in 99% 13C diamond that are robust to decoherence. At magnetic field strengths ranging from 550 - 900 G, these transitions are observable by optically detected magnetic resonance (ODMR), and exhibit linewidths narrowed by factors as high as ~130 at room temperature over typical electron-type transitions observed from this spin system. We anticipate the use of these decoherence-protected transitions, in combination with dynamical decoupling methods, for storage of quantum information.
Microwave-Free 13C Hyperpolarization of Diamond Particles Enabled by Magic Angle Spinning and NV Centers
Nuclear hyperpolarization from optically pumped color centers in solids offers an alternative to conventional microwave-driven dynamic nuclear polarization (DNP). Diamond can host the nitrogen vacancy (NV) center, whose ground spin state can be readily polarized by light at room temperature, making diamond a candidate platform for nuclear hyperpolarization. We report 13C nuclear hyperpolarization in randomly oriented diamond particles with sizes ranging from 0.2 to 2 μm, both at natural 13C abundance (1.1 %) and at 20 % isotopic enrichment, at magnetic fields of 7.1 T and 9.4 T. The protocol combines optical illumination with magic angle spinning (MAS) and does not require microwave irradiation. By investigating the nuclear polarization as a function of the MAS frequency between 0 and 6 kHz at the magnetic field of 7.1 T, we find maximum light-induced polarization enhancements of 280-fold for the isotopically enriched sample and 411-fold for the natural abundance sample. Under continuous illumination, steady-state absolute 13C polarization levels above 0.1 % are reached. A model involving optical pumping of NV centers and spin dynamics near level anticrossings (LACs) in three-spin clusters formed by NV, a substitutional nitrogen (P1) and 13C is used to describe these findings. The protocol strongly mitigates the effect of the anisotropy of the NV spin Hamiltonian, allowing more than 99.9% of NV orientations to participate in the polarization transfer process. These results represent a first step toward transferring nuclear polarization from diamond particles to external nuclei, with potential applications in sensitive and high-resolution NMR at room temperature.
The ability to measure and manipulate the quantum state of a single spin in a solid state system opens up a broad range of powerful applications ranging from nano probes to quantum information processing. Over the past few years, a number of ground breaking experiments have been conducted on paramagnetic nitrogen vacancy defect centers in diamond, including up to 3-qubit entanglement, single-shot-readout of a nuclear spin, selective access of two coupled centers and magnetic, electric and thermographic sensing at the nanoscale with promising properties in some cases exceeding most currently known techniques. Yet, almost all of the experiments conducted so far focus on centers deeply buried in the diamond, which is undesirable especially for sensing applications, but also in terms of scalability and electronic access to the information. In this work we focus on the spin physics of centers only few nanometers below the surface, where the unique properties of the center are strongly influenced by the external environment. We coherently manipulated and detected single spins at ambient temperature by combining optically detected magnetic resonance with single molecule spectroscopy using a confocal microscope. We measured the spin dephasing behavior and the phase relaxation time and examined the primary sources of decoherence. Furthermore, we observed effects of water, atmosphere and paramagnetic molecules on the coherence and readability of spins in nanodiamonds and demonstrated ways to preserve the coherence using external magnetic fields and a number of different dynamic decoupling pulse sequences. In addition, we measured couplings to proximal nuclear spins by continuous wave spectroscopy and to molecules on the surface by double electron electron resonance. Also, we demonstrate execution of the refined Deutsch-Jozsa algorithm on a nitrogen vacancy center in a nanodiamond. Finally, we propose new technological approach for realtime measurements of magnetic fields using a single spin in diamond. In test measurements using external fields and spatially resolved measurements of the field from a magnetic microwire a sensitivity of a few uT / sqrt(Hz) was achieved.
Nitrogen vacancy centers in diamond (NVs) are point defects well suited to quantum sensing of magnetic fields. NV spin states can be initialized and read out optically with high spatial resolution, enabling detection of pL-scale volumes of nuclear spins. Using Coherently Averaged Synchronized Readout (CASR), standard NMR spectroscopy techniques such as free decay, spin echo, and PGSE have been performed with Hz-scale spectral resolution using NV-diamond sensors. However, using NV detection for conventional high-resolution NMR at multi-tesla fields is challenging due to the need to manipulate NV electronic spins at resonance frequencies 100 GHz or higher. Low-field J-coupling spectroscopy provides an alternative path to chemical resolution in a regime more easily accessible to NVs. Here, we demonstrate homonuclear and heteronuclear J-coupling spectroscopy using an NV-NMR spectrometer based on permanent magnets operating at $\sim$890 kHz proton Larmor frequency (bias magnetic field $\sim21mT).ThisfieldstrengthenableschemicalcharacterizationbasedonJ−couplingusingsequencessuchasSynchronizedEcho(SyncE)andSpin−EchoDoubleResonance(SEDOR),whichdonotrequirethestrongchemicalshiftdispersionandpristinefieldhomogeneityofhigh−fieldNMR.ThefrequencyrangeiseasilydetectedbyNVsusingstandardXYdynamicaldecouplingsequencesandiswell−suitedforapplyingOverhauserDNP,whichcanboostprotonsignalbytwoordersofmagnitude.WeacquireinitialNV−NMRmeasurementsofT_1,T_2,andOverhauserDNPinglycerolbeforeadvancingtoSEDORspectroscopyofmethanol−^{13}Candamethanol−^{13}C/acetonitrile−2−^{13}$C mixture at sample volumes $\sim$50 pL, in which we demonstrate measurement of 1JCH couplings and resolution between species. We also acquire a homonuclear J-coupling spectrum of a natural-abundance propylene carbonate sample.
Individual nuclear spins in diamond can be optically detected through hyperfine couplings with the electron spin of a single nitrogen-vacancy (NV) center; such nuclear spins have outstandingly long coherence times. Among the hyperfine couplings in the NV center, the nearest neighbor 13C nuclear spins have the largest coupling strength. Nearest neighbor 13C nuclear spins have the potential to perform fastest gate operations, providing highest fidelity in quantum computing. Herein, we report on the control of coherences in the NV center where all three nearest neighbor carbons are of the 13C isotope. Coherence among the three and four qubits are generated and analyzed at room temperature.