Dynamical sensitivity control of a single-spin quantum sensor

Abstract

The Nitrogen-Vacancy (NV) defect in diamond is a unique quantum system that offers precision sensing of nanoscale physical quantities at room temperature beyond the current state-of-the-art. The benchmark parameters for nanoscale magnetometry applications are sensitivity, spectral resolution, and dynamic range. Under realistic conditions the NV sensors controlled by conventional sensing schemes suffer from limitations of these parameters. Here we experimentally show a new method called dynamical sensitivity control (DYSCO) that boost the benchmark parameters and thus extends the practical applicability of the NV spin for nanoscale sensing. In contrast to conventional dynamical decoupling schemes, where π pulse trains toggle the spin precession abruptly, the DYSCO method allows for a smooth, analog modulation of the quantum probe’s sensitivity. Our method decouples frequency selectivity and spectral resolution unconstrained over the bandwidth (1.85 MHz–392 Hz in our experiments). Using DYSCO we demonstrate high-accuracy NV magnetometry without |2π| ambiguities, an enhancement of the dynamic range by a factor of 4 · 103, and interrogation times exceeding 2 ms in off-the-shelf diamond. In a broader perspective the DYSCO method provides a handle on the inherent dynamics of quantum systems offering decisive advantages for NV centre based applications notably in quantum information and single molecule NMR/MRI.

Sensitivity optimization for NV-diamond magnetometry

“…However, such measurements are often complicated by nonidealities in certain sequences' filter functions, such as sensitivity to harmonics or the presence of side lobes (Cywiński et al, 2008). Recently, ac magnetometry protocols with enhanced spectral resolution have been demonstrated, such as the dynamic sensitivity control (known as DYSCO) sequence and its variants (Lazariev et al, 2017;Romach et al, 2019), which provide simpler, single-peaked filter functions at the cost of reduced sensitivity. Additional dynamical decoupling sequences with increased spectral resolution or other advantages have been employed (Boss et al, 2017;Schmitt et al, 2017;Glenn et al, 2018;Hernández-Gómez et al, 2018) or proposed (Cywiński et al, 2008;Zhao, Wrachtrup, and Liu, 2014;Poggiali, Cappellaro, and Fabbri, 2018).…”

Nitrogen-vacancy centers in diamond for nanoscale magnetic resonance imaging applications

“…Dynamical decoupling schemes are based on π pulse trains which command the spin precession abruptly. Recently, dynamical sensitivity control (DYSCO) has been proposed, aiming to provide smooth and analog sensitivity modulation [25]. In this control method, |2π| ambiguities are removed without sacrificing accuracy.…”

Ultra-high dynamic range quantum measurement retaining its sensitivity

“…Their improvement of the dynamic range compared to a sequence with 16 π-pulses was about 26, and they explored the effect of the phase of the measured field in depth. Besides, one of the advantages of the previously reported dynamical sensitivity control 11 was the increase in the range by 4000 times, up to a theoretical maximum of 5000 times. Their uncertainty for a single measurement was about double that of a similar standard measurement, while the required multi-measurement for the large range worsened the sensitivity further (which is the uncertainty times ) by with N ϕ the number of phases applied in their method (the more phases, the larger the range, but each phase requires an additional measurement).…”

“…For quantum-sensing applications, nitrogen-vacancy (NV) centres in diamond have attracted considerable attention due to their exceptional quantummechanical properties 1,2 , including long spin-coherence times 3,4 , and due to their great potential for far-field optical nanoscopy [5][6][7][8] . Furthermore, an increase in sensitivity can be gained for alternating current (AC) field sensing by prolonging the NV spin coherence with dynamical decoupling of the centre's spin from its environment 2,3,[9][10][11][12] . Therefore, AC field sensing is applied in various areas of physics, chemistry and biology: to detect single spins [13][14][15] , for nuclear magnetic-resonance of tiny samplevolumes [16][17][18][19][20] , for nanoscale magnetic-resonance imaging 13,[21][22][23] and to search for new particles beyond the standard model 24,25 .…”