Fig. 3
From: Tracking the ultrafast motion of an antiferromagnetic order parameter
TR modulation of the SHG anisotropy. a Measured ground state SHG anisotropy. b Time-dependent normalised correlated SHG intensity at different points of the anisotropy (see “Methods”). c Time dependence of the relative amplitude change. d Time dependent rotation angle of the SHG anisotropy after excitation. Solid lines are fits. The error bars denote standard errors of the means determined from 16 consecutive measurements. e Red and blue curves are calculated SHG anisotropies according to \(P6_3^\prime cm\prime\) (\({\mathbf{S}}\parallel \hat x\)) and \(P6_3^\prime c\prime m\) (\({\mathbf{S}}\parallel \hat y\)) symmetry, respectively. A spin canted by an angle α leads to a superposition of Sx- and Sy-related SHG contributions. Their interference causes a rotation and amplitude change of the SHG anisotropy (yellow curve)
