Fig. 2: SHG imaging of ferroaxial domains in NiTiO3 using circularly polarized fundamental light.

a, b Two-dimensional maps of SH intensity obtained with (a) right-handed circularly polarized (RCP) and (b) left-handed circularly polarized (LCP) light. Bright and dark regions correspond to either A+ or A− ferroaxial domains. c Transmission optical microscopy image of the area corresponding to the SHG images of (a) and (b). Branch-like patterns in (c) correspond to TiO2 impurities. d Three-dimensional image of SH intensity at the same area as (a) and (b).