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Doping of optical fibers with NV(-) nanodiamonds is discussed for three technological approaches involving solid and hollow core geometries. Magnetic sensing performance is assed with sensitivity of 500 nT/sqrt(Hz) achieved for 24 cm long samples.

Integration of optically active diamond particles with glass fibers is a powerful method of scaling diamond's magnetic sensing functionality. We propose a novel approach for the integration of diamond particles containing nitrogen-vacancy centers directly into the fiber core. The core is fabricated by stacking the preform from 790 soft glass canes, drawn from a single rod dip-coated with submicron diamond particles suspended in isopropyl alcohol. This enables manual control over the distribution of nanoscale features, here – the diamond particles across the optical fiber core. We verify this by mapping the diamond distribution in the core using confocal microscopy. The particles are separated longitudinally by 12–29 μm, while in the transverse plane a separation of approximately 1.5–2.2 μm is observed, corresponding to the individual cane diameter in the final fiber, and without significant agglomeration. The fiber's magnetic sensitivity is confirmed in optically detected magnetic resonance recorded with a coiled, 60-cm-long fiber sample with readout contrast of 1.3% limited by microwave antenna coverage. Moreover, magnetic-field dependence of the NV─ fluorescence intensity is demonstrated in the absence of microwaves, allowing magnetometric applications with a large (from 0 to 35 mT) B-field dynamic range.

In this paper, a novel fabrication technology of atomic force microscopy (AFM) probes integrating cantilever tips with an NV-rich diamond particle is presented. Nanomanipulation techniques combined with the focused electron beam-induced deposition (FEBID) procedure were applied to position the NV-rich diamond particle on an AFM cantilever tip. Ultrasonic treatment of nanodiamond suspension was applied to reduce the size of diamond particles for proper geometry and symmetry. The fabricated AFM probes were tested utilizing measurements of the electrical resistance at highly oriented pyrolytic graphite (HOPG) and compared with a standard AFM cantilever performance. The results showed novel perspectives arising from combining the functionalities of a scanning AFM with optically detected magnetic resonance (ODMR). In particular, it offers enhanced magnetometric sensitivity and the nanometric resolution.

We apply a laser and two nearly degenerate microwave fields upon an ensemble of nitrogen-vacancy centers in diamond and observe magnetic resonance structures with two-component, composite shapes of nested Lorentzians with different widths. One component of them undergoes regular power-broadening, whereas the linewidth of the other one becomes power-independent and undergoes field-induced stabilization. We show that the observed width stabilization is a general phenomenon that results from competition between coherent driving and non-conservation of populations that occur in open systems. The phenomenon is interpreted in terms of specific combinations of state populations that play the role of bright and dark states.

We present a photoluminescence (PL) and Raman spectroscopy study of various diamond samples that have high concentrations of nitrogen-vacancy (NV) color centers up to multiple parts per million (ppm). With green red, and near infrared (NIR) light excitation, we demonstrate that while for samples with a low density of NV centers the signals are primarily dominated by Raman scattering from the diamond lattice, for higher density of NVs we observe a combination of Raman scattering from the diamond lattice and fluorescence from the NV centers, while for the highest NV densities the Raman signals from diamond are completely overwhelmed by the intense NVs fluorescence. However, under NIR excitation, Raman diamond signatures can be observed for some diamonds. These observations reveal different roles of two mechanisms of light emission and contradict the naive belief that Raman scattering enables complete characterisation of a diamond crystalline sample.

This publisher’s note amends the funding and acknowledgments of [Opt. Mater. Express 12(2), 444 (2022).10.1364/OME.447426].

We present an experimental study of the longitudinal and transverse relaxation of ensembles of negatively charged nitrogen-vacancy (NV−) centers in a diamond monocrystal prepared by 1.8 MeV proton implantation. The focused proton beam was used to introduce vacancies at a 20 µµm depth layer. Applied doses were in the range of 1.5×1013 to 1.5×1017 ions/cm2. The samples were subsequently annealed in vacuum which resulted in a migration of vacancies and their association with the nitrogen present in the diamond matrix. The proton implantation technique proved versatile to control production of nitrogen-vacancy color centers in thin films.

We demonstrate a simple dip-coating method of covering standard AFM tips with nanodiamonds containing color centers. Such coating enables convenient visualization of AFM tips above transparent samples as well as using the tip for performing spatially resolved magnetometry. Full Text: PDF References G. Binnig, C. F. Quate, C. Gerber, "Atomic Force Microscope", Phys. Rev. Lett. 56, 930 (1986). CrossRef F .J. Giessibl, "Advances in atomic force microscopy", Rev. Mod. Phys. 75, 949 (2003). CrossRef S. Kasas, G. Dietler, "Probing nanomechanical properties from biomolecules to living cells", Eur. J. Appl. Physiol. 456, 13 (2008). CrossRef C. Roduit et al., "Stiffness Tomography by Atomic Force Microscopy", Biophys. J. 97, 674 (2009). CrossRef L. A. Kolodny et al., "Spatially Correlated Fluorescence/AFM of Individual Nanosized Particles and Biomolecules", Anal. Chem. 73, 1959 (2001). CrossRef L. Rondin et al., "Magnetometry with nitrogen-vacancy defects in diamond", Rep. Prog. Phys. 77, 056503 (2014). CrossRef C. L. Degen, "Scanning magnetic field microscope with a diamond single-spin sensor", Appl. Phys. Lett. 92, 243111 (2008). CrossRef J. M. Taylor et al., "High-sensitivity diamond magnetometer with nanoscale resolution", Nat. Phys. 4, 810 (2008). CrossRef J. R. Maze et al., "Nanoscale magnetic sensing with an individual electronic spin in diamond", Nature 455, 644 (2008). CrossRef L. Rondin et al., "Nanoscale magnetic field mapping with a single spin scanning probe magnetometer", Appl. Phys. Lett. 100, 153118 (2012). CrossRef J. P. Tetienne et al., "Nanoscale imaging and control of domain-wall hopping with a nitrogen-vacancy center microscope", Science 344, 1366 (2014). CrossRef R. Nelz et al., "Color center fluorescence and spin manipulation in single crystal, pyramidal diamond tips", Appl. Phys. Lett. 109, 193105 (2016). CrossRef G. Balasubramanian et al., "Nanoscale imaging magnetometry with diamond spins under ambient conditions", Nature 455, 648 (2008). CrossRef P. Maletinsky et al., "A robust scanning diamond sensor for nanoscale imaging with single nitrogen-vacancy centres", Nat. nanotechnol. 7, 320 (2012). CrossRef L. Thiel et al., "Quantitative nanoscale vortex imaging using a cryogenic quantum magnetometer", Nat. nanotechnol. 11, 677 (2016). CrossRef F. Jelezko et al., "Single spin states in a defect center resolved by optical spectroscopy", Appl. Phys. Lett. 81, 2160 (2002). CrossRef M. W. Doherty et al., "The nitrogen-vacancy colour centre in diamond", Phys. Rep. 528, 1 (2013). CrossRef C. Kurtsiefer, S. Mayer, P. Zarda, H. Weinfurter, "Stable Solid-State Source of Single Photons", Phys. Rev. Lett. 85, 290 (2000). CrossRef A. Gruber, A. Drabenstedt, C. Tietz, L. Fleury, J. Wrachtrup, C. Von Borczyskowski, "Scanning Confocal Optical Microscopy and Magnetic Resonance on Single Defect Centers", Science 276, 2012 (1997). CrossRef F. Dolde et al., "Electric-field sensing using single diamond spins", Nat. Phys. 7, 459 (2011). CrossRef K. Sasaki et al., "Broadband, large-area microwave antenna for optically detected magnetic resonance of nitrogen-vacancy centers in diamond", Rev. Sci. Instrum. 87, 053904 (2016). CrossRef A. M. Wojciechowski et al., "Optical Magnetometry Based on Nanodiamonds with Nitrogen-Vacancy Color Centers", Materials 12, 2951 (2019). CrossRef I. V. Fedotov et al., "Fiber-optic magnetometry with randomly oriented spins", Opt. Lett. 39, 6755 (2014). CrossRef

Efficient collection of photoluminescence arising from spin dynamics of nitrogen vacancy (NV) centers in diamond is important for practical applications involving precise magnetic field or temperature mapping. These goals may be realized by the integration of nanodiamond particles with optical fibers and volumetric doping of the particles alongside the fiber core. That approach combines the advantages of robust axial fixation of NV diamonds with a direct spatial overlap of their fluorescence with the guided mode of the fiber. We developed a suspended core silicate glass fiber with 750 nm-diameter nanodiamonds located centrally in the 1.5 µm-core cross-section along its axis. The developed fiber probe was tested for its magnetic sensing performance in optically detected magnetic resonance measurements using a 24 cm-long fiber sample, with the NV excitation and fluorescence collection from the far ends of the sample and yielding optical readout contrast of 7% resulting in 0.5 µT·Hz-1/2 magnetic field sensitivity, two orders of magnitude better than in earlier designs. Thanks to its improved fluorescence confinement, the developed probe could find application in magnetic sensing over extended fiber length, magnetic field mapping or gradiometry.

We report on studies of a diamond sample with a strong gradient of NV− concentration (between 4 and 36 ppm over 1.5 mm) created by inhomogeneous irradiation with an electron beam. The sample was characterized by spatially resolved luminescence and ODMR spectra and spatial distributions of NV− concentration, strain splitting, and relaxation times T1, T2. Such inhomogeneous sample may find applications in designing optimum conditions for numerous applications in spectroscopy and sensorics.

Transparent ceramics in the form of yttrium oxide (Y2O3) doped with La and Nd and pure yttrium as a reference material were successfully prepared via modified EDTA gel process and hot isostatic pressure sintering. Their structure and microstructure were examined by means of scanning electron microscopy and X-ray diffraction, which revealed the high density and single-phase character of these materials. Their optical and magneto-optical properties were also analyzed. Emission spectra of Nd0.1La0.1Y1.8O3 after excitation performed with a continuous 808 nm laser beam showed strong and sharp emission lines. The luminescence lifetime was also investigated. The doped material exhibited a high Verdet constant of over 1000 deg/T m. The figure of merit was calculated in the VIS spectrum. The investigated transparent oxide ceramics can be considered a promising material for application in lasers and magneto-optical devices.

A Faraday rotation measurement system with an alternating magnetic field was built to study magneto-optical properties of transparent materials in wide spectrum range (300-1100 nm) with a resolution under 1 nm. An experiment setup was work based on double modulating light technique and the signal was detected by the sensitive balanced polarimetry and it was decoded with precise digital potentiostat. The device is coupled with a mechanical splitter in order to improve precision of measurements and eliminate an electrical artifacts between coils and photodiodes. The apparatus was tested by measuring the wavelength dependence of Verdet constants and the absorbance coefficient for a well-known material - BK-7 glass. In this paper magneto-optical properties of TSAG crystal and Y2O3 translucent ceramic were investigated as a function of temperature in UV-VIS-IR spectrum.

The aim of the work was to synthesize Y 2 O 3 , La 0.1 Y 1.9 O 3 , Nd 0.1 Y 1.9 O 3 , Nd 0.1 La 0.1 Y 1.8 O 3 and Nd 0.12 La 0.1 Y 1.78 O 3 powders using EDTA gel processes, and to examine the physicochemical properties of transparent sinters obtained from these powders. A part of this goal was the determination of the influence of various dopants on the optical properties of yttria. X-ray diffraction studies of the investigated powders and sinters confirmed their single-phase composition, which indicated incorporation of lanthanum and neodymium into the crystal lattice of yttria. Scanning electron microscopy (SEM) combined with density measurements indicated that the studied sinters had high density. An optical transparency over 50% was obtained for the Y 2 O 3 sinter in the wavelenght range of 450–1100 nm. The influence of dopants on the level of transmittance was also investigated.

Transparent La0.1Nd0.1Y1.8O3 ceramics were prepared by use of the ethylenediaminetetraacetic acid gel process followed by sintering by hot isostatic pressing. The structure and morphology of the powders and bulk samples and the optical properties of bulk samples were investigated by use of x-ray diffraction (XRD), scanning electron microscopy, visible and near-infrared reflectance spectroscopy, and study of magneto-optic (Faraday) effects. The powders consisted of many agglomerates of fine, oval particles. XRD studies of the powder and bulk sample confirmed their single-phase composition, and spectrophotometric and magneto-optical studies in the range 500–1000 nm revealed their potential for application as an optical materials.

Nitrogen-vacancy color centers in diamond are a very promising medium for many sensing applications such as magnetometry and thermometry. In this work, we study nanodiamonds deposited from a suspension onto glass substrates. Fluorescence and optically detected magnetic resonance spectra recorded with the dried-out nanodiamond ensembles are presented and a suitable scheme for tracking the magnetic-field value using a continuous poly-crystalline spectrum is introduced. Lastly, we demonstrate a remote-sensing capability of the high-numerical-aperture imaging fiber bundle with nanodiamonds deposited on its end facet.

W artykule zaprezentowano centra barwne azot-wakancja (NV) w diamentach w roli czujnika temperatury nowego typu. Krótko omówiono ostatnie doniesienia naukowe oraz podsumowano techniki wytwarzania diamentów z centrami NV. Zaproponowano nowatorskie wykorzystanie centrów NV do badania materiałów termoelektrycznych Nitrogen vacancy color centers in diamond (NVs) as a new type of temperature sensors were presented in the article. Recent progress in the field of NV thermometry and summarize the techniques of NVs manufacturing was briefly discussed. The use of NVs for characterization of thermoelectric materials was proposed.

We present results of our research on two-field (two-frequency) microwave spectroscopy in nitrogen-vacancy (NV-) color centers in a diamond. Both fields are tuned to transitions between the spin sublevels of the NV- ensemble in the 3A2 ground state (one field has a fixed frequency while the second one is scanned). Particular attention is focused on the case where two microwaves fields drive the same transition between two NV- ground state sublevels (ms=0 -> ms=+1). In this case, the observed spectra exhibit a complex narrow structure composed of three Lorentzian resonances positioned at the pump-field frequency. The resonance widths and amplitudes depend on the lifetimes of the levels involved in the transition. We attribute the spectra to coherent population oscillations induced by the two nearly degenerate microwave fields, which we have also observed in real time. The observations agree well with a theoretical model and can be useful for investigation of the NV relaxation mechanisms., 17 pages

We present an experimental study of the longitudinal electron-spin relaxation of ensembles of negatively charged nitrogen-vacancy (NV ) centers in diamond. The measurements were performed with samples having different NV- concentrations and at different temperatures and magnetic fields. We found that the relaxation rate T1-1 increases when transition frequencies in NV- centers with different orientations become degenerate and interpret this as cross-relaxation caused by dipole-dipole interaction., Comment: 11 pages, 9 figures

Negatively-charged nitrogen-vacancy (NV$^-$) centers in diamond have generated much recent interest for their use in sensing. The sensitivity improves when the NV ground-state microwave transitions are narrow, but these transitions suffer from inhomogeneous broadening, especially in high-density NV ensembles. To better understand and remove the sources of broadening, we demonstrate room-temperature spectral "hole burning" of the NV ground-state transitions. We find that hole burning removes the broadening caused by magnetic fields from $^{13}$C nuclei and demonstrate that it can be used for magnetic-field-insensitive thermometry., Main text: 5 pages, 4 figures. Supplement: 6 pages, 3 figures

The ability to create time-dependent magnetic fields of controlled polarization is essential for many experiments with magnetic resonance. We describe a microstrip circuit that allows us to generate strong magnetic field at microwave frequencies with arbitrary adjusted polarization. The circuit performance is demonstrated by applying it to an optically detected magnetic resonance and Rabi nutation experiments in nitrogen-vacancy color centers in diamond. Thanks to high efficiency of the proposed microstrip circuit and degree of circular polarization of 85% it is possible to address the specific spin states of a diamond sample using a low power microwave generator., 4 pages, 7 figures, nitrogen-vacancy, microwave circular polarization, spin-state addressing