Figure 6: (a) line selective population by intra-dot excitation. FSS is not observed since the two states with their total spin of are degenerated. (b) Detection polarization-selective PL spectra of the line measured under the excitation. Red curve is a result of co-circular () detection, while the blue curve is a result of cross-circular () detection. The degree of circular polarization defined by is as high as 0.85 without external magnetic field.