Figure 2
From: Broadband polarization conversion with anisotropic plasmonic metasurfaces
Experimental setup of the optical vortex based spiral interferometry for directly characterizing the phase retardation through the metasurface sample of T-shaped antenna array. LP: linear polarizer, QWP: quarter-wave plate, BS: beam splitter, OL: objective lens, SPP: spiral phase plate (with the perspective-view SEM image shown in the lower inset).
