Fig. 3

Expected functionality, structural parameters and sample pictures of the meta-device I. a The proposed meta-device I is expected to covert the incident LCP light to a focused vortex SPP in the NF channel and reflect the incident RCP light to a spatial vortex beam in the FF channel, with topological charges of two vertices being 1 and -3, respectively. Distributions of b \({\Phi}_{{\text{Str}}}\left(\overrightarrow{r}\right)\), c \(\xi \left(\overrightarrow{r}\right)\), d\({L}_{u}\left(\overrightarrow{r}\right)\) and e \({L}_{v}\left(\overrightarrow{r}\right)\) of the meta-device under design. f SEM image of the fabricated sample, with its zoomed-in images shown in g and the inset