Figure 2. Time-resolved NMR of near-surface ¹H spins.

(a) XY8-3 correlation signal (circles) from protons in a solid polymeric mixture (sample A) in contact with the diamond surface. The yellow trace corresponds to an exponentially damped sinusoid with time constant of 21 μs and frequency equal to ∼1 MHz. The vertical axis indicates the contrast in a scale relative to the NV Rabi amplitude. (b) Comparison between the ¹H-NMR spectra obtained with an XY8-10 sequence (blue squares) and after Fourier transformation of the XY8-3 correlation protocol shown in a (yellow circles). The blue and yellow traces, respectively, indicate Lorentzian fits to each data set, accompanied by their corresponding full-width at half-maximum values. Both curves are vertically displaced for clarity.