“…Resonant excitation of a single quantum emitter combined with fluorescence detection was a long-term experimental challenge mainly due to the inability to spectrally discriminate the weak fluorescence from the strong excitation scattering. This difficulty, however, has been successfully overcome in the past decade by two different approaches: dark-field confocal excitation based on polarization discrimination 1,2,3,4,5 , and orthogonal excitation-detection based on spatial mode discrimination 6,7,8,9,10,11,12,13,14 . Both approaches demonstrate a strong capability to significantly suppress laser scattering and thus are widely adopted in various experiments, for example, observation of spin-photon entanglement 5,15,16 , demonstration of dressed states 2,7,12,17,18,19,20,21,22,23,24,25,26 , and coherent manipulation of confined spins 3,27,28,29,30 .…”