(a), (c) SEM images of the gratings and grooves working as the polarization rotator, (b) and (d) the corresponding optical images of (c) and (e), respectively. On (a) and (b), the TE-BSW was transformed into TM-BSW during the reflection by the grooves (T-G). On (c) and (d) the TM-BSW was transformed into the TE-BSW. The double-headed white arrows in (b and d) indicate the orientation of the incident polarization. The scale bar (10 μm) on (a) is applicable for (a-b), and the scale bar on (c) is applicable for (c-d).