a Resonant fluorescence emission spectrum as a function of the pump power and detuning of the detected radiation, δω01 = ω − ω01. Pp is the power from the RF source while Pq is the corresponding power on the qubit. Inset: a schematic of the triplet transitions in the dressed-state picture, where the qubit energy levels split by Ω due to strong driving, creating three transitions with frequencies ω01 − Ω, ω01 and ω01 + Ω. b Rabi splitting Ω (dots) vs. drive amplitude, extracted from (a). The black line is the linear fit to obtain the attenuation in the input line which is A = −145 dB. c Power spectral density at −116 dBm power at the sample. The black lines are individual fits to the linewidths of the three peaks, yielding Γ2/2π = 141 ± 2 kHz and Γ1/2π = 276 ± 5 kHz. The arrows correspond to the transitions in the inset of (a).