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Continuous observation of continuous dynamical decoupling

(Left) Spectrogram and (right) power spectral density (PSD, normalized) of a 90ms long Faraday rotation signal. (Inset) The spin-1 dressed state energy diagram; the mean and difference of transition frequencies are the dressed Larmor frequency and quadratic shift, respectively. The sidebands about the carrier are associated with the |1⟩ ↔ |3⟩ (gold), |2⟩ ↔ |3⟩ (turquoise), and |1⟩ ↔ |2⟩ (lavender) transitions. Magnetic field fluctuations are manifest as asymmetric frequency modulation of the |1⟩ ↔ |3⟩ and |2⟩ ↔ |3⟩ sidebands, while the |1⟩ ↔ |2⟩ transition remains relatively unaffected. The corresponding peaks in the PSD have linewidths 102 Hz, 97 Hz, and 24 Hz (near transform-limited), respectively. The |2⟩ ↔ |3⟩ peaks are significantly skewed (mean magnitude of Pearson skew coefficient is 0.88) while the |1⟩ ↔ |2⟩ peaks are unskewed (respectively 0.08).