Fig. 2
ESR properties of the driven central spin. a \(Q\) factor of the Rabi oscillations (purple) and inverse \(1/e\)-decay time of the Rabi oscillation visibility (pink) as a function of Rabi frequency. We define the visibility by taking the maximum and minimum of the Rabi curve, over a \(\pi\)period. Hartmann–Hahn resonances between electron-nuclear states at \(\Omega \approx {\omega }_{{\rm{nuc}}}^{z}\) and \(\Omega \approx 2{\omega }_{{\rm{nuc}}}^{z}\) depicted in the inset emerge as an accelerated decay. b Calculated nuclear spectral density for Indium (purple, \(I\) = 9/2) and Arsenic (pink, \(I\) = 3/2). The inset indicates the transitions \(\Delta m=1\) and \(\Delta m=2\) considered in our model, which are strain-allowed to first order. In the intermediate-power regime where \(\Omega \approx \Delta m\,{\omega }_{{\rm{nuc}}}^{z}\), \({({\tau }_{1/e})}^{-1}\) is equal up to a factor \(2\pi\) to this density of states, after convolution with the width of the ESR transition (see Supplementary Note 4)
