Photoluminescence Decomposition Analysis: A Technique to Characterize N - V Creation in Diamond

Abstract

Treatment of lab-grown diamond by electron irradiation and annealing has enabled quantum sensors based on negatively-charged nitrogen-vacancy (NV -) centers to demonstrate record sensitivities. Here we investigate the irradiation and annealing process applied to 28 diamond samples using a new ambient-temperature, all-optical approach. As the presence of the neutrally-charged nitrogenvacancy (NV 0 ) center is deleterious to sensor performance, this photoluminescence decomposition analysis (PDA) is first employed to determine the concentration ratio of NVto NV 0 in diamond samples from the measured photoluminescence spectrum. The analysis hinges on (i) isolating each NV charge state's emission spectrum and (ii) measuring the NVto NV 0 emission ratio, which is found to be 2.5˘0.5 under low-intensity 532 nm illumination. Using the PDA method, we measure the effects of irradiation and annealing on conversion of substitutional nitrogen to NV centers. Combining these measurements with a phenomenological model for diamond irradiation and annealing, we extract an estimated monovacancy creation rate of 0.52˘0.26 cm -1 for 1 MeV electron irradiation and an estimated monovacancy diffusion coefficient of 1.8 nm 2 /s at 850˝C. Finally we find that irradiation doses Á 10 18 e -/cm 2 deteriorate the NVdecoherence time T2 whereas T1 is unaffected up to the the maximum investigated dose of 5ˆ10 18 e -/cm 2 . :1906.11406v1 [cond-mat.mes-hall] arXiv

Sensitivity optimization for NV-diamond magnetometry

“…10. Measurements of the diffusion constant D have yielded ∼1.1 nm 2 =s at 750°C (Martin et al, 1999) and 1.8 nm 2 =s at 850°C (Alsid et al, 2019), suggesting values for D 0 in agreement with an independently measured upper bound (Acosta et al, 2009), and in moderate agreement with firstprinciples theoretical calculations (Fletcher and Brown, 1953); see the Appendix, Sec. 10.…”

“…(i) Dephasing time T Ã 2 : In current realizations, dephasing times in application-focused broadband NV − ensemble magnetometers (Kucsko et al, 2013;Clevenson et al, 2015;Barry et al, 2016;Chatzidrosos et al, 2017) are typically T Ã 2 ≲ 1 μs. Considering the physical limit T Ã 2 ≤ 2T 1 (Levitt, 2008;Alsid et al, 2019;Bauch et al, 2019), with longitudinal relaxation time T 1 ≈ 6 ms for NV − ensembles (Jarmola et al, 2012), a maximum T Ã 2 ≈ 12 ms is theoretically achievable, corresponding to a sensitivity enhancement of ≈ 100 times. Although the feasibility of realizing T Ã 2 values approaching 2T 1 remains unknown, we consider improvement of T Ã 2 to be an effective approach to enhancing sensitivity; see Sec.…”

“…The simple analysis stated here is complicated by the uncertainty in D 0 and E a , as well as the presence of other vacancies, vacancy aggregates, dislocations, surfaces, etc., which can also trap vacancies, but are beyond the scope of this paper. For additional detail and discussion, see Alsid et al (2019).…”

Charge state dynamics and optically detected electron spin resonance contrast of shallow nitrogen-vacancy centers in diamond

“…We observe a significantly higher fraction of emission between the zero phonon line (ZPL) of NV 0 (575 nm) and the ZPL of NV − (637 nm) in sample F, as well as a peak at 575 nm [ Fig. 2(a)], indicating a higher steady-state population of NV 0 [31]. This higher NV 0 steady-state population contributes to background fluorescence, decreasing the OD-ESR contrast proportionally.…”

Chemical vapour deposition diamond single crystals with nitrogen-vacancy centres: a review of material synthesis and technology for quantum sensing applications

“…There is near equal excitation at 514 nm and in this case, the strengths of the zero-phonon lines is a good indicator of the relative concentrations of the two NV charge states [167]. In order to more precisely measure the charge state ratio, decomposing the PL spectrum obtained with a 532 nm excitation has also been proposed as a more straightforward approach [177].…”