Fig. 3: Probing bath correlations to quantify noise spectrum under drive.
From: Protecting qubit coherence by spectrally engineered driving of the spin environment
a Pulse sequence used to probe the surface spin bath, and (b) corresponding spectrum with Δν = 0, tss = 60 ns, τ = 20 μs, Ωss/2π = 9.7 MHz, and an NV π-pulse of 80 ns. c Experimental spin bath dynamics, obtained by measuring NV coherence as a function of pulse length tss for different excitation line-widths Δν and for Ωss/2π = 8.7 MHz. Increasing Δν accelerates the damping of the Rabi oscillations, eventually reaching an overdamped regime. d Noise spectral densities obtained by Fourier transformation of the fitted DEER signals in (c) and normalized so that \(2\int\nolimits_{0}^{\infty }S(\omega )d\omega /2\pi =1\). Gray shaded area represents the Hahn-echo filter function corresponding to a sequence duration of τ = 10 μs. Error bars represent ± one standard error.
