Abstract The TR12 color center in diamond is a self‐interstitial spin defect capable of room‐temperature atomic‐scale vector magnetometry for detecting magnetic fields of arbitrary orientation and magnitude. Measurements using the TR12 center show that the sensing dynamic range can potentially outperform that of NV centers in diamond. The powerful quantum sensing capabilities of TR12 place it as a strong alternative candidate for quantum sensing in diamond, especially in extreme magnetic fields. However, its sensitivity in existing literature is relatively low in the µT/√Hz range. This work examines the spatial distributions of TR12 centers fabricated by high‐energy carbon irradiation on an E‐grade diamond along the ion irradiation cascade. A detailed study of photoluminescence intensity, optically detected magnetic resonance contrast, and linewidth is conducted. By varying locations along ion cascades of line irradiations with different fluences, the highest sensitivity of 1.2 nT/√Hz is achieved at three orders of magnitude higher than demonstrated in existing literatures. Coherent manipulation of triplet spin states in these ensembles is evident from Rabi oscillation measurements, with decoherence times of ≈0.47 µs at the surface and ≈ 0.42 µs at the end‐of‐range. These findings significantly enhance the potential of TR12 for quantum sensing applications.
Abstract The TR12 color center in diamond is a self‐interstitial spin defect capable of room‐temperature atomic‐scale vector magnetometry for detecting magnetic fields of arbitrary orientation and magnitude. Measurements using the TR12 center show that the sensing dynamic range can potentially outperform that of NV centers in diamond. The powerful quantum sensing capabilities of TR12 place it as a strong alternative candidate for quantum sensing in diamond, especially in extreme magnetic fields. However, its sensitivity in existing literature is relatively low in the µT/√Hz range. This work examines the spatial distributions of TR12 centers fabricated by high‐energy carbon irradiation on an E‐grade diamond along the ion irradiation cascade. A detailed study of photoluminescence intensity, optically detected magnetic resonance contrast, and linewidth is conducted. By varying locations along ion cascades of line irradiations with different fluences, the highest sensitivity of 1.2 nT/√Hz is achieved at three orders of magnitude higher than demonstrated in existing literatures. Coherent manipulation of triplet spin states in these ensembles is evident from Rabi oscillation measurements, with decoherence times of ≈0.47 µs at the surface and ≈ 0.42 µs at the end‐of‐range. These findings significantly enhance the potential of TR12 for quantum sensing applications.
Point defects in insulators are considered promising candidates for quantum technologies. In keeping with this, we present an extensive optically-detected magnetic resonance (ODMR) study at room-temperature on individual TR12 centers (ZPL at 471nm), which are known in the literature since 1956. In this work we found TR12 centers to show a strong ODMR signal under optical saturation. These observed defects were created in high-purity epitaxial layers of diamond by standard irradiation and annealing processes. From the analysis of the ODMR spectra along with antibunching measurements and coherent population trapping, we proposed the energy level structure of TR12 center, consisting of ground state and excited state singlets complemented by a metastable triplet in between. Mapping the fluorescence dependence of the center on an external magnetic field and on the polarization of laser excitation, allows us to identify twelve inequivalent orientations for TR12 centers. This includes the exact orientations of the dipole transition and the triplet axes in the diamond lattice in full agreement with the results of modeling based on the proposed level structure. Furthermore, a static Jahn-Teller effect was detected through fluorescence switching between two levels at low optical excitation power, directly observable in the real-time fluorescence signal for various polarization of laser excitation. Based on these results we discuss the prospects of the TR12 center in diamond for quantum sensing and quantum information processing.
Nitrogen Vacancy (NV) centers are point defects in diamond that allow magnetic field sensing based on Optically Detected Magnetic Resonance (ODMR). They are processed in ultrapure single-domain CVD grown diamond crystals and can be operated at room temperature. This results in solid-state sensors with a wide variety of applications. Ensemble of NV centers can be used to perform wide-field magnetic imaging with sensitivity in the nT range. Single NV centers can also be processed, which allows sensing at the atomic scale. This possibility, combined with its unique coherence properties, make NV center an ideal candidate for quantum sensing.
NV- center has been paid attention as a quantum sensor for highly sensitive detection of magnetic field, electric field, temperature and strain, etc.. Electron beam irradiation followed by subsequent thermal annealing is known as the effective procedures to create NV- center in diamond. The electron irradiation generates vacancies in diamond and the annealing enables vacancies to diffuse in the lattice. Then diffused vacancies are captured by nitrogen atoms, and as a result, NV centers are created. In addition, substitutional nitrogen atom at a lattice site (P1 center) also acts as a donor for NV center, the charge state of NV centers changes from neutral (NV0) to NV-. Creation high concentration of ensemble NV- centers is needed to achieve high sensitively sensing. The magnetic sensitivity is proportional to the reciprocal of the number of NV centers and T2 (spin coherence time), i.e., high concentration NV- centers with long T2 increase the sensitivity. P1 center has an important role for being a component of NV- centers and acting as donor to the NV center. But it also plays a role as decoherence source (decrease in magnetic field sensitivity). Therefore, it is important to create high concentration of NV- centers considering the amount of P1 centers. In current study, we investigate irradiation fluence dependence of the creation behavior of NV centers in type-Ib diamonds by using electron spin resonance (ESR) and photo-luminescence (PL) to understand the creation mechanism of NV- center. The values of T2 are also evaluated by Hahn-echo measurement, since it is one of the key parameters for highly sensitive magnetometry. Then, we discuss the creation mechanism of NV centers based on concentrations of defects.
Creating dense and shallow nitrogen-vacancy (NV) ensembles with good spin properties is a prerequisite for developing diamond-based quantum sensors exhibiting better performance. Ion implantation is a key enabling tool for precisely controlling spatial localization and density of NV color centers in diamond. However, it suffers from a low creation yield, while higher ion fluences significantly damage the crystal lattice. In this work, we realize N2+ ion implantation in the 30–40 keV range at high temperatures. At 800 °C, NV's ensemble photoluminescence emission is three to four times higher than room temperature implanted films, while narrow electron spin resonance linewidths of 1.5 MHz, comparable to well-established implantation techniques, are obtained. In addition, we found that ion fluences above 2 × 1014 ions/cm2 can be used without graphitization of the diamond film, in contrast to room temperature implantation. This study opens promising perspectives in optimizing diamond films with implanted NV ensembles that could be integrated into quantum sensing devices.
The negatively charged nitrogen vacancy center in diamond is widely used for quantum sensing due to the sensitivity of the spin triplet in the electronic ground state to external perturbations such as strain and electromagnetic fields, which makes it an excellent probe for changes in these perturbations. The spin state can be measured through optically detected magnetic resonance, which is most commonly achieved by detecting the photoluminescence after exciting the spin-triplet transition. Recently, methods have been proposed and demonstrated that use the absorption of the infrared singlet transition at 1042 nm instead. These methods, however, require cryogenic temperatures or external cavities to enhance the absorption signal. Here, we report on our efforts to optimize the magnetometer sensitivity at room temperature and without cavities. We reach a sensitivity of 18 pT / Hz , surpassing previously reported values, and a calculated shot-noise limit of 5 pT / Hz . We also report on a defect that is native to diamond grown by chemical vapor deposition and thus absent in high-pressure high-temperature diamond, the excitation of which impacts the measured singlet absorption signal.
The negatively charged nitrogen vacancy center in diamond is widely used for quantum sensing due to the sensitivity of the spin triplet in the electronic ground state to external perturbations such as strain and electromagnetic fields, which makes it an excellent probe for changes in these perturbations.The spin state can be measured through optically detected magnetic resonance, which is most commonly achieved by detecting the photoluminescence after exciting the spin-triplet transition.Recently, methods have been proposed and demonstrated that use the absorption of the infrared singlet transition at 1042 nm instead.These methods, however, require cryogenic temperatures or external cavities to enhance the absorption signal.Here, we report on our efforts to optimize the magnetometer sensitivity at room temperature and without cavities.We reach a sensitivity of 18 pT/ √ Hz, surpassing previously reported values, and a calculated shot-noise limit of 5 pT/ √ Hz .We also report on a defect that is native to diamond grown by chemical vapor deposition and thus absent in high-pressure high-temperature diamond, the excitation of which impacts the measured singlet absorption signal.