The relationship between the phase difference ${\phi }_p$ and the pump-polarization extinction ratio was incorrectly expressed as ${\phi }_p=\pm {\tan }^{-1}({10}^{-\mathrm{PER}/10})$ on p. 2707 in Ref. [1], where PER is the measured pump-polarization extinction ratio and $+$ and $-$ correspond to right- and left-handed elliptically polarized pump light states, respectively. This is due to a mistake during the manuscript preparation.

The correct relationship is ${\phi }_p=\pm 2\times a\tan ({10}^{-\mathrm{PER}/10})$. The revision does not influence the analysis of the experimental results and the conclusions of this Letter.