Figure 3.

The sixteen cross-correlation measurements needed for the violation of the Clauser-Horne-Shimony-Holt inequality. The angles on the left specify how much the polarization detection angle α for the exciton (blue) and biexciton (red) is rotated with respect to the rectilinear basis in the laboratory reference frame. For each set of rotation the degree of correlation C _b is extracted by measuring all four combinations between the biexciton (XX and $\overline{\mathrm{XX}}$) and exciton (X and $\overline{\mathrm{X}}$) photons. The insets show a magnification of the zero time delay peak.