Fig. 1. Schematic of the surface electromagnetic wave hologram. (a) The writing process, where metal surface is an x−y plane, (b) The reading process.

Fig. 2. Design of the groove pattern used to couple a plane wave in free space to a focusing SPP wave on a metal surface. Panels (a)–(d), (e)–(h), and (i)–(l) are for the incident angles θ=0°, θ=15°, and θ=30°, respectively. Panels (a), (e), and (i) show the interference intensity pattern, while (b), (f), and (j) show the groove pattern. (c), (g), (k), and (d), (h), (l) display the reconstruction result of the intensity distribution in the x−y plane and x−z plane where y=−8  μm, respectively.

Fig. 3. Influence of groove depth and incident angle on the coupling efficiencies. (a) Groove depth h. (b) Incident angle θ.

Fig. 4. Design of the groove pattern used to couple a plane wave to dual-points SPPs on a metal surface. For θ=0°, (a) is the interference intensity pattern and (b) is the groove pattern. For reconstruction intensity, (c) is the x−y plane and (d) is x−z plane when y=−8  μm. For θ=15°, (e) is the interference intensity pattern and (f) is the groove pattern. For the reconstruction intensity, (g) is the x−y plane and (h) is the x−z plane when y=−8  μm. (i) The influence of the groove depth on the coupling efficiency for θ=0° and θ=15°.